Why is traffic worse some days than it is on others?

bigpinkelephant

I have noticed that traffic is always light on a Friday morning but heavy on a Friday evening. Also Tuesday mornings tend to be heavier. Why is this? I work 8.30 - 5.30 every day.

Creamy Goodness

some people take mondays off to have a 3-day weekend and are coming back on to the road on tuesday.

fridays are light because some people will take public transport in so that they can go out socialising after work. friday evenings are heavy as a load of people will head home to their home counties.

8vjohn

I completely agree. I think fri mornings are quiet because people get paid thurs night and go overboard so they can't get up on time fri morning.

edanto

And then when it's wet in the morning, more people take their cars.

probe

Much of the congestion is caused by "invisible" system failures in the background. Traffic signal control computer failures (forcing the local brain dead traffic signal box on the side of the road to make decisions it is not equipped to make), loop detector or other failures (causing traffic flow data to computer systems to cease or be incorrect), and bad system design (where the detector/control model implementation is not properly engineered to effectively manage variances in traffic flow under every condition).

The SCATS system used in Dublin is particularly vulnerable to the latter, because it requires a significant amount of customisation of the setup at each junction to work with precision, and does not have upstream queue detection. It wastes a lot of valuable green time at each node to create green waves. While the SCOOT system used in Cork and Limerick requires less customisation, and is very tight creating green waves, to deal with varying traffic conditions, the local authorities have tied the systems hands in terms of decision making latitude by imposing inappropriate min and max cycle and phase times which don’t allow it to react to extreme variations in traffic flows (be they rush hour on a wet Friday afternoon or 4AM on Christmas day). And the SCOOT control software/hardware platform seems to break down a lot. Typical British engineering unreliability.

A traffic light controlled system can deal with very heavy traffic levels if the cycle time is allowed to rise proactively – as much as is necessary, and before things get bad, – say 240 seconds to deal with peak flows. Ditto for cycle time flexibility. Eg if the lights remained green for say 3 mins non-stop along a busy defined priority route in extreme circumstances, at peak times where necessary, huge amounts of traffic would move in the momentum of flow. Artificial timing ceilings, lack of proactivity in the model, and hardware failures are one the biggest parts of the problem. The other is the absence of a universal high quality public transport system, a la Luas.

You need intelligently designed priority routes and intelligently designed priority for public transport to make the most of the scarce roadspace in urban areas. And a quality control system that ensures that traffic sensor measurements being fed into the model are 99.99% accurate and system failures are repaired immediately.

.probe

Red Alert

I'd love to see what would happen with the 'brakes off' so to speak some day, where the SCATS is allowed complete freedom to make decisions. I wonder might it do a better job than when they 'help' it out?

probe

bigpinkelephant wrote: »

I have noticed that traffic is always light on a Friday morning but heavy on a Friday evening. Also Tuesday mornings tend to be heavier. Why is this? I work 8.30 - 5.30 every day.

In many continental countries, flexitime is the norm or legally mandated. Traffic congestion and peak loads on public transport systems are greatly exacerbated by large numbers of people being forced to be at work at a particular time. This is a huge waste of resources. If people could go and come from work at random times that suited themselves – with core working hours (eg 10-12 and 14-16h) where everyone was available, where necessary, – but putting in the same total number of hours every week, journey times would be greatly reduced in urban areas. Add to that an increase in the level of telecommuting for all or part of the work week and the country would get a big increase in efficiency and reduction in health service expenditure.

You may think that flexitime is not suited to all job types. However flexitime is viral – e.g. with less people travelling per minute at peak times you need less bus and train drivers to turn up at peak times, less people to answer telephone calls at peak times – virtually all demands on services get spread out more evenly over the working day.

.probe

probe

Red Alert wrote: »

I'd love to see what would happen with the 'brakes off' so to speak some day, where the SCATS is allowed complete freedom to make decisions. I wonder might it do a better job than when they 'help' it out?

The problem with SCATS is that it is working on incomplete data ie without upstream data at each junction. My remarks about increasing/reducing cycle and phase time limits to the max and min were mainly addressed at SCOOT installations.

However both SCATS and SCOOT are obsolete because they still rely tinkering with cycles and phases of the individual traffic controllers.

An intelligent state of the art system (such as used in Zurich) has no phases and cycles - the central computer system drives the entire show (except during a local system failure when the controller resorts to local mode). It monitors the feedback from detectors minute by minute to identify and report any detector failure. Each type of vehicle is assigned a different priority level. The number of vehicles in a queue is known precisely. An emergency vehicle on call gets a higher priority than a tram running late. A tram running on time gets a lower priority than a tram running late. A truck climbing a hill gets a higher priority (less chance of a red light) compared with a car, because the truck stopping and taking off after the light turns green spews out so much more pollution.

If there is no vehicle waiting on a side road, you don't see a green light on that side road. If a car turns up, chances are the light turns green as the vehicle approaches if there is no traffic on the priority route - eliminating the need to break and accelerate from stop for no reason.

It takes a large amount of computing power to run this in a large city - but computing power is cheap - a lot cheaper than people's wasted time and the waste of energy caused by traffic chaos.

As in all continental countries pedestrian crossings operate in conflict with vehicular traffic - because it is safer and allows more time for vehicular traffic. eg if traffic is green North-South, pedestrians get a green signal North south - and if a vehicle is turning East or West it has to give priority to the pedestrian. Result - there are no pedestrian crossing phases which reduce the efficiency of Irish traffic light controlled junctions by 20-30%. Drivers become more aware of the pedestrian, and pedestrians are more on the lookout for vehicles.

Pedestrian accidents are among the highest in Europe in Ireland (and Britain) because in these countries alone (a) it takes ages to get a green light to cross the road because pedestrian crossing phases operate separately from vehicular phases - so most people don’t wait for the light before crossing and (b) pedestrians have priority on black and white zebra crossings in the "British isles" – leading to a false sense of security for the pedestrian. On the continent, if you brazenly walk on a black and white zebra crossing when there is traffic approaching and the driver hasn’t signalled you that it is OK to cross, chances are you will be blown off the road! And perfectly right too, because you are creating a hazard in so doing. Marked pedestrian crossings should be designated places to safely cross the road when signalled to do so, or there is no traffic coming.

If proof were needed, consider that when Dublin City Council introduced beeping signals at pedestrian crossings, many brain dead people just walked out on the road when they heard the beep noise like robots – ignoring oncoming traffic or which pedestrians the beep noise was intended for. The ill conceived system has turned many members of the public into morons.

.probe

Chris_533976

Having a tractor on the road can create a fake jam. Get 50 cars behind a tractor and it looks like terrible traffic. Its the same number of cars as normal, its just that they've been bunched by the tractor and it appears there are more of them.

de breeze

Probe can you say if there is any interactivity or intelligence SCATS, SCOOT or whatever designed into traffic signals here in Dun Laoghaire? The Council are obsessed with adding more and more signalled junctions - Cherrywood Rd Loughlinstown is a case in point. These seem to have the effect of increasing congestion which is maybe what was intended.

It is incredibly frustrating to be stopped at multiple red lights on say the Blackrock bypass at 5.00 am when there is no crossing traffic whatsoever....

de breeze

de breeze wrote: »

It is incredibly frustrating to be stopped at multiple red lights on say the Blackrock bypass at 5.00 am when there is no crossing traffic whatsoever....

There are a few sets like that around Tallaght that just appear to "work the rule" without any regard to traffic levels, dumb lights have road sensors that appear to do nothing! :mad:
There are others that you can "switch" just by driving up slowly to them, we need more of these.

HydeRoad

Is it not a case in point that some authorities deliberately obstruct the idea of green waves, to 'reduce' the average speed of traffic, and deter motorists from approaching the city?

I drive a taxi by night. I drive all the main city corridors regularly. So regularly, that I know a lot of the traffic light sequences off by heart.

Roads like along the Grand Canal, the Tallaght Road as mentioned, the Frascati Road, etc. Driving along these roads at night, you are guaranteed every single yellow light along their length, and the full sequence of each traffic light operation. In practice, this means, that if you drive at some totally unreasonable speed above 80kph in a city zone, you might just make it through. If you do the designated speed limit, you are stopped by a red light at every junction.

This results in more braking, more acceleration, more fuel usage, more wear and tear (which must be horrendous on a vehicle driving these streets all night long) and an unnecessarily greater 'carbon footprint.' For the taxi passenger too, for example, it means paying for a whole lot of extra 'waiting time' on the meter, for all these unnecessary stops.

More serious by far, however, is the obvious reward for the guy who willingly breaks the speed limit, and runs red lights, out of frustration for lack of progress on deserted nighttime roads. How many times have I seen near misses on wide, dangerous crossroads, or vehicles driving at killer speeds, just to make that light before it turns red?

Surely safe driving WITHIN the speed limit, could be encouraged for EVERYONE, by organising green waves on main corridors, with green lights appearing precisely based on the speed and distance between junctions? It is done all over the UK, and you know if you do the regulation 30 or 40mph limit you will see the greean lights appear as you approach, but not before. No incentive to drive faster, as you will end up braking anyway.

probe

de breeze wrote: »

Probe can you say if there is any interactivity or intelligence SCATS, SCOOT or whatever designed into traffic signals here in Dun Laoghaire? The Council are obsessed with adding more and more signalled junctions - Cherrywood Rd Loughlinstown is a case in point. These seem to have the effect of increasing congestion which is maybe what was intended.

It is incredibly frustrating to be stopped at multiple red lights on say the Blackrock bypass at 5.00 am when there is no crossing traffic whatsoever....

While Dun Laoghaire/Rathdown has always been a basket case for traffic light management, there is no real interactivity in the traffic signal system (SCATS) used anywhere in the Dublin area.

SCATS is really an old fashioned “fixed time” system that uses a computer to modify phase and cycle times in arrears, based on traffic flows over the stop line. If you look on the road near the stop line you can see the SCATS detector loops in the ground – too close to the traffic lights to measure the size of the queue or react in a timely manner to vehicles arriving near a junction. Call it Windows 95.

The reason they can have count down wait time displays for pedestrians in the Dublin area is that the system is not interactive. If it was interactive in real time, the system wouldn’t be able to predict 30 or 60 seconds in advance of when you could cross the road. SCATS requires lots of human input in set-up and keeping the system up to date, and monitoring from a control centre – ie it is like having a dog and barking yourself! It runs on Windows. It uses a decentralised architecture – ie the entire system is not running in a single computer centre – which increases maintenance costs and the time to repair faults. SCATS is also used in Waterford.

The next generation of traffic control systems (call it Windows 98 – eg SCOOT, used in Cork and Limerick) continuously runs a forecast model to predict the flow of traffic and adjust the signals on a just in time basis. It has upstream detectors (typically around 100 m before the traffic signal stop line) so it knows how many vehicles are queuing at a red light (allowing it to make decisions based on known queue lengths). When the light is green the upstream detector alerts the system to any additional vehicles approaching the lights, giving the system the information it needs to decide if it should keep the lights green for another few seconds to let the approaching vehicles through without stopping them. Where there are large queues of vehicles waiting at a red light and only one or two vehicles approaching the green light, it might decide to stop the latter.

It can thus factor these data into the decision making process to minimise overall journey times across the network and reduce pollution caused by start stop driving.

All this is old technology.

Zurich system: (A centralised second by second totally interactive, almost perfect traffic management system, running on Unix)

http://www.vs-plus.com/pub/9601/e/9601f.htm
http://cat.inist.fr/?aModele=afficheN&cpsidt=3611301

.probe

AlekSmart

Excellent postings probe !

They confirm what I have been thinking for a long time now.

As far as the mainstream media (Talk to Joe,Independent,Times etc) are concerned the mere presence of a desktop somewhere in Civic Offices Traffic Control Room is enough to merit the tag "Hi-Tech"

Any attempt to discuss the role of Traffic Flow Management is short circuited by the term SCATS,as if it were the ultimate in such matters.
This attitude has facilitated DCC and the Dept of the Environment for far too long in Dublin.

I feel that at least some of the T21 dosh should have been diverted in to the replacement of SCATS with even a Windows XP version if you will.

There is little doubt but that the traffic signalling and active management in Dublin is seriously wanting and that there is much to be gained from making some relatively small adjustments to the manner in which the City Traffic Signal infrastructure operates.

One can but hope I suppose ???? :eek:

Using that logic, I think some of the ones in Tallaght must use sy-dos 0.7

gurramok

HydeRoad wrote: »

Is it not a case in point that some authorities deliberately obstruct the idea of green waves, to 'reduce' the average speed of traffic, and deter motorists from approaching the city?

I drive a taxi by night. I drive all the main city corridors regularly. So regularly, that I know a lot of the traffic light sequences off by heart.

Roads like along the Grand Canal, the Tallaght Road as mentioned, the Frascati Road, etc. Driving along these roads at night, you are guaranteed every single yellow light along their length, and the full sequence of each traffic light operation. In practice, this means, that if you drive at some totally unreasonable speed above 80kph in a city zone, you might just make it through. If you do the designated speed limit, you are stopped by a red light at every junction.

This results in more braking, more acceleration, more fuel usage, more wear and tear (which must be horrendous on a vehicle driving these streets all night long) and an unnecessarily greater 'carbon footprint.' For the taxi passenger too, for example, it means paying for a whole lot of extra 'waiting time' on the meter, for all these unnecessary stops.

More serious by far, however, is the obvious reward for the guy who willingly breaks the speed limit, and runs red lights, out of frustration for lack of progress on deserted nighttime roads. How many times have I seen near misses on wide, dangerous crossroads, or vehicles driving at killer speeds, just to make that light before it turns red?

Surely safe driving WITHIN the speed limit, could be encouraged for EVERYONE, by organising green waves on main corridors, with green lights appearing precisely based on the speed and distance between junctions? It is done all over the UK, and you know if you do the regulation 30 or 40mph limit you will see the greean lights appear as you approach, but not before. No incentive to drive faster, as you will end up braking anyway.

What you describe happens on the north bound direction on the whole of Gardiner st from the river(tara st end) to the junction with Dorset st , it encourages speeding to pass about 7 sets of lights.
I've experienced this without fail every evening(7pm+) where speeders are rewarded with constant greens and speed limit obeyers get the reds at each set of lights.

Funnily enough, the southbound direction on the same route is green freeflow.(Traffic from somewhere southbound has priority over somewhere other(traffic from Tara st) with loss of synch in both directions)

And when you reach Dorset st and travel northwards on the street, the green flow comes into operation which is totally opposite of the constant stop start scenario!

Stark

gurramok wrote: »

What you describe happens on the north bound direction on the whole of Gardiner st from the river(tara st end) to the junction with Dorset st , it encourages speeding to pass about 7 sets of lights.
I've experienced this without fail every evening(7pm+) where speeders are rewarded with constant greens and speed limit obeyers get the reds at each set of lights.

Similar thing happens on the N11. Very annoying.

fricatus

Excellent post, Probe!!!

probe wrote: »

SCATS is really an old fashioned “fixed time” system...

It runs on Windows...

SCATS is also used in Waterford.

Hmmm... that explains a lot, hehe.

I read in the local press about that system a few years back when it was introduced, and the local journalist's favourite stock phrase, "state of the art" was used to describe it.

Pity the city council hadn't spoken to Probe first

de breeze

Probe thanks for the post about Dun Laoghaire. Very good info especially re Zurich.

The council are now proposing to take out two roundabout junctions on the N11 link - Glenageary Rd upper and 'the graduate' and replace them with signals. Unbelievably this is being done:

a. To facilitate a development opposite the graduate pub and
b. to improve access to N11/M50 - objective in Co Development plan.

This will add the number of signalled junctions on this short corridor to about 12! I must go out and count them today....

Worse the 'engineers' set the signal timing on Cherrywood rd Dual carriageway to favour crossing traffic. This 'ruse' is aimed at preventing speeding and has been in operation for as long as I can remember.

It would appear that the Council idiots have no vision whatsoever on progressing management techniques for traffic - just keep firing in dumb traffic signals at every opportunity.

Needs to say the latest 'scheme' is subject of a public 'consultation'. But is there any point in objecting - does anyone care!!!

Zoney

probe wrote: »

While the SCOOT system used in Cork and Limerick requires less customisation, and is very tight creating green waves, to deal with varying traffic conditions, the local authorities have tied the systems hands in terms of decision making latitude by imposing inappropriate min and max cycle and phase times which don’t allow it to react to extreme variations in traffic flows (be they rush hour on a wet Friday afternoon or 4AM on Christmas day).

Match days or other jam-causing conditions (diversions etc.) usually result in the major junctions in Limerick city now being switched to a default mode at the lights - flashing amber for the through road at a junction, and flashing red on the side roads. This works surprisingly well, although getting out of side roads can be tricky. In some cases, a guard directs traffic at some of the busier junctions/roundabouts.

I hadn't seen this bypass arrangement used before the council installed new lights at all the junctions in the last year or two. I wonder if any new control systems were installed, or is it just that the local controllers (Siemens) are that bit more flexible.

I've seen the same arrangement used in Cork on occasion too - makes sense I guess if they use the same control system.

AlekSmart

One of the benefits of the Internet is threads such as this which allow folks to tease out the administrative nonsense which Ireland appears to be filled with.

The Traffic Signal situation is a case in point.

it`s quite obvious that at some point the Local Authority Roads and Traffic people have recieved "Directions","Guidelines" or "Advice" from their paymasters,most likely the Dept of the Environment.

In these long buried inter-office memos I suspect a Policy Instruction was given (In Code (Às Gailge) to regard Traffic Signals as a dei facto Speed Control measure rather than as an active traffic-control measure.

There`s not a county borough in the state which does not have a collection of poorly configured or downright unsafe Traffic Signals whose programming and operation defies all logic

My particular favourites are those large and incredibly fraught Roundabouts (Walkinstown in Dublin for example) which suddenly accquire Pedestrian Signals immediately after one manages to negotiate the Roundabout.

Interesting too is the reluctance of Local Authorities to install complimentary barriers to direct pedestrians towards the designated crossing instead of the time honoured wandering abroad which constitutes normal behaviour here.

It all comes back to Planning and Implimentation,two items which this country does not do....full stop.

Lets just sit for a while and watch how much of Transport 21`s €34 Billion simply disappears on frippery long before any tangible result appears.... :eek:

gurramok

Stark wrote: »

Similar thing happens on the N11. Very annoying.

Co-inicidentally i experienced that coming from Bray direction yesterday.

Never made it through any set of lights at the speed limit but about 10% of the rest(it must of been 90%+ breaking speed limit) going faster than me did manage to get past the lights ahead.

Classic way of encouraging speeding.:mad:

probe

Stark wrote: »

Similar thing happens on the N11. Very annoying.

The N11 is mainly controlled by SCATS, even though most of it is not located in Dublin city.

SCATS is incapable of controlling an “expressway” like the N11 efficiently, because it is incapable of managing a dynamic greenwave, especially one on a divided highway which feeds into a city where the dynamics of flows vary enormously between the northbound and southbound directions over a 24h period.

SCATS can’t optimise the offset between one node and the next (because the model doesn’t have precise data indicating when a platoon of vehicles is going to hit the next traffic signal down the road). The offset in the timing difference between two sets of lights – e.g. you are driving down the N11 and get a green light, and you observe the next set of lights ahead turning green 5 seconds later – even though you mightn’t arrive at the next set of lights for another 15 seconds and you are the first car in the pack. That represents 15 seconds of wasted green time that could be used by other phases, at no time cost to you. That time-waste is repeated over and over at hundreds of sets of traffic lights all over Dublin, adding up to a massive waste of resources over a 24 hour period. Not to mention the extra pollution generated by stopped traffic coming from other directions that could be moving while you are on approach to the junction ahead.

In addition, if everyone sees a red light up ahead, they are not going to push their speed - if the light ahead changes to green at precisely the correct time, people won't have to touch their brakes either as they come close to the next stop line - providing they keep a safe distance from the vehicle in front.

Where you have proper interactive traffic control based on upstream detection, the lights don’t turn green until the platoon of vehicles gets close to the next signal. And if it is intelligently designed, such as Swiss VS-Plus system, the model does everything possible to keep the lights green until the last vehicle in the platoon has got through – because keeping the unbroken momentum of a platoon of vehicles is a key driver to maximising the efficiency of a road network. The strategy also eliminates the incentive to speed one’s way through the lights.

The only way that you can efficiently manage greenwaves on roads such as the N11 is using a system that incorporated upstream vehicle detection, so that the greenwave is demand driven by the approach of the platoon of vehicles – rather than being fixed in advance based on estimated timings. At the end of the day the maintenance of greenwaves is not the core priority, which should be to minimise journey times and pollution across the entire network. Real time traffic flow measurements have to be precise, and the same applies to traffic light timings, otherwise one ends up with a massive waste of resources - including peoples' valuable time getting from A to B.

.probe

http://www.vs-plus.com/prod/vs-plus/VS-PLUS%20Details.pdf

probe

Zoney wrote: »

Match days or other jam-causing conditions (diversions etc.) usually result in the major junctions in Limerick city now being switched to a default mode at the lights - flashing amber for the through road at a junction, and flashing red on the side roads. This works surprisingly well, although getting out of side roads can be tricky. In some cases, a guard directs traffic at some of the busier junctions/roundabouts.

I hadn't seen this bypass arrangement used before the council installed new lights at all the junctions in the last year or two. I wonder if any new control systems were installed, or is it just that the local controllers (Siemens) are that bit more flexible.

I've seen the same arrangement used in Cork on occasion too - makes sense I guess if they use the same control system.

I don’t know why they turn traffic signals to flashing amber/red during sporting events in Limerick. SCOOT has no problem dealing with bursts of traffic arising from an exodus from a venue – providing the upstream sensors are far enough upstream on the exit routes so that the model is fully aware of the scale of the queue waiting to exit an area. It also needs cycle and phase time latitude so that its hands aren’t tied – a cycle time ceiling of say 4 minutes and very long ceilings on phase times.

If you leave drivers to deal with flashing amber lights during heavy traffic, each vehicle is going to take longer to move through a junction due to the uncertainty as to who has right of way. In the same way as if the traffic lights were turned off. Flashing amber is only suitable in very light traffic conditions, and at, for example pedestrian crossings so the driver can move on if nobody is crossing. A green light allows a driver to proceed with more confidence and get out of the way.

There is no legal basis for flashing red lights. It is not a European or international standard. Intuitively I would take flashing red to be a warning that the traffic signals are defective. If anything they create even more doubt and confusion in people’s minds – and a lack of clarity in signalling and signposting can lead to accidents.

.probe

chipclub

It appears to be country wide. Drogheda has atrocious traffic light signalling, no doubt designed as a deterrent to M1 traffic using the town to by-pass the toll bridge. I drive through every morning at 6:30am and every day it is different. The last two mornings I got through the town without stopping but every day last week I was stopped at 5 consecutive sets of lights. There is nothing more frustrating than being the first car at a red light, moving off on green and seeing the next lights 50m ahead turn red before you get there.

Do they even have a "hi-tech" Windows solution in Drogheda? The lights appear to be on a simple timer.

markpb

Cheers probe for those posts! I agree about SCATS being outdated but I think there's a second problem which also affects traffic: ignorance.

Yesterday morning at 8am a van parked in the bus lane/stop on Dolier St and disrupted all the buses trying to pull in, pull out, drop off passengers, etc. It was so bad that 20 minutes later when he was moved on by the gardai at the behest of the RTCC, Dolier St, Memorial Bridge, Georges Quay, Burgh Quay and O'Connell Bridge had all come to a standstill. It took over 25 minutes to get from Connolly Stn to College Green.

This morning some fool tried to turn right across Malahide rd onto Kilmore rd at a restricted junction. All the cars behind backed up and then started to merge into the bus lane. Buses and taxis backed up to let them in and when they cleared, the cars didn't move out of the bus lane so the bus couldn't get to the junction in time for the lights. One car managed to cause at least half a mile tailback in both lanes because he didn't read the sign.

People underestimate the problems they cause when buses have to maneuver round them. They don't see the chaos behind them or realise how long it'll remain bad after they've stopped being idiots and left the scene.

IanCurtis

probe wrote: »

In many continental countries, flexitime is the norm or legally mandated. Traffic congestion and peak loads on public transport systems are greatly exacerbated by large numbers of people being forced to be at work at a particular time. This is a huge waste of resources. If people could go and come from work at random times that suited themselves – with core working hours (eg 10-12 and 14-16h) where everyone was available, where necessary, – but putting in the same total number of hours every week, journey times would be greatly reduced in urban areas. Add to that an increase in the level of telecommuting for all or part of the work week and the country would get a big increase in efficiency and reduction in health service expenditure.

You may think that flexitime is not suited to all job types. However flexitime is viral – e.g. with less people travelling per minute at peak times you need less bus and train drivers to turn up at peak times, less people to answer telephone calls at peak times – virtually all demands on services get spread out more evenly over the working day.

.probe

Flexi-time is available in our office, but most of the drones come in for 9am anyway and are stuck in traffic at it's worst.

Figure that one out!

Stark

You don't really benefit much from coming in at 10 vs 9 with Dublin traffic. The people who make the greatest savings in commute time seem to be the people who are in before 8:30.

I am "fortunate" to work 12hr shifts 8 - 8 day & night, I miss the worst of the traffic but still get stuck at brain dead lights with no other traffic to be seen.
I've even see Gards cars jump the lights in Tallaght SC out of sheer frustration!