Cycling safety at 40 Dublin junctions to benefit from €400k “smart” tech fund

— Focus will be on large junctions first.

— Left hooks and not clearing large junctions to be tackled.

People cycling in the Dublin City area could benefit as what is mostly decades-old technology is re-branded “smart” and used at 40 junctions, which have yet to be defined.

The funding of “smart” tech is in line will the focus on this within the programme for the Velo-City 2019, an international cycling conference, which Dublin City Council is hosting next year and which the Department of Transport highlighted today that it is a key sponsor.

It is unclear what exact will be all the methods used at junctions, but they Department of Transport says it includes people on bicycles not have enough time to cross a junction before opposing signals go green and collisions between people on bicycles and drivers turning left.

The funding will also include technology to count bicycles at different locations which is seen by international planners and engineers as a key tool in planning for safe cycle route.

The core technologies to be used is bicycle-sensitive inductive loops in the ground and “smart” thermal imaging detectors — both are basically old technology, although greater use of them has been made internationally in cycling safety in recent years.

Transport minister Shane Ross — pictured above for today’s announcement — said: “I want to encourage more people to cycle and I realise that safety is a concern to many, so I am continuing to invest in safety measures for cyclists. This €400,000 will improve safety for cyclists at 40 key junctions across Dublin City Centre and is a great example of my Department and the National Transport Authority working with local authorities to improve cycling and walking infrastructure generally.”

He also highlighted that that the infrastructure side of BusConnects will include 200km of cycle route upgrades across Dublin.

With no realisation that it has left Irish local authorities to rely on 12-year-old guidance from another country, the Department of Transport press release said that: “Within the Dublin City Council area traffic signals are set to operate with safety timings which are normally calculated using the UK Department for Transport advisory leaflet 1/06. The safety times referred to are the ‘intergreens’ ie time from end of end of green on one approach to start of green on an opposing approach. It is assumed vehicles are travelling at a uniform speed at or close to the posted speed limit.”

“This approach allows for safety at junctions for vehicular traffic but raises issues when the proportion of bicycles at an intersection starts to rise due to the relatively slow speed of cyclists in an urban environment and the variability of speed across types of cyclists. In Copenhagen the average speed of cyclists is 15km/hour and this seems to be replicated in several cities around the world. The issue therefore for a cyclist is that on a 50km/h road they are travelling through the intersection at a third of the speed of cars and take three times as long to safely pass through,” it said.

The Department added: “One approach therefore is to change the calculations at junctions from 50km/h to 15km/h and add on the additional intergreen time, however this is wasteful for a number of reasons.” It said that this included “The longer the intergreen time the less green time available for Trams, Buses, Taxis and general traffic and so increasing congestion and journey times for public transport” and that at some times of the day there are less people cycling.

According to Copenhagen city council, while the overall average speed of bicycle users in Copenhagen is around 16km/h or more, on main routes this is higher and the city has “green wave” with a required speed of 20km/h to keep going without seeing a red light on the route. A Dutch local authority also confirmed to only this week that the average speed for bicycle users is closer to 20km/h on their city’s main cycle routes, especially on larger roads or otherwise away from the city centre.

Some media reports on the Department’s statement have miss-reported that the funding is just for the city centre, as the statement said that the junctions to be targeted will be “especially the junctions in the 60km/h areas”, which are all outside the city centre except around where the Chapelizod bypass (former N4) meets the South Circular Road.

While the solution of active detection of bicycles is best practice, the analyses does not fit with standard findings on cycling speeds around large junctions, and international practices around reducing the overall length of the traffic light sequences or ‘cycles’, which is viewed to be better for walking, cycling, and public transport.

This thinking of reducing the traffic light ‘cycle’ time is also in Irish guidance, the Manual for Urban Roads and Streets. It was also in a draft of the Dublin City Centre Transport Study, but was missing from the final copy.

The Department of Transport statement said: “Initially the installation would be at the physically big junctions in the city centre and surrounding areas and especially the junctions in the 60km/h areas. It is now therefore proposed to identify 40 junctions within the City Council area where this detection can be installed and where benefits for cyclists can be quickly achieved, works will commence in 2018. This would be a phase 1 list with work then commencing on a phase 2 list once the benefits of this approach have been quantified and realised.”


  1. The intergreen time at a lot of junctions where I even notice it exists it pretty short. Less than a second I would guess. I don’t think tripling it would really affect the throughput of junctions that much. It is frustrating but unsurprising that adding an extra two seconds of red for motorists is given equal concern as cyclist safety.

    So long as we continue to turn a blind eye to motorists ploughing through red lights based on the premise that the first few seconds don’t count it’s kind of pointless anyway. People will just change from thinking the first two seconds don’t count to assuming the first five seconds don’t count.

  2. The car driver could reasonably reason : “The lights are timed to let a bike through, so I can pass the stop line late as long as I get across the junction no slower than a bike that might have passed the stop line just as the light left the green state.”

  3. When thinking about intergreens and how long cyclists will need to clear a junction, average cycling speeds and the number of cyclists using the junction are both irrelevant and I have no idea why the Department seems to think they matter. A light has to go red before the slowest cyclist in town, waiting at the red light, no longer has time to clear the junction before traffic coming the other way starts flowing. Safety timings have to be calculated on the basis of the speed of the very slowest cyclist plus a margin of error. Average speeds shouldn’t come into it, and cyclists deserve to be able to trust a green light even on routes that don’t see many cyclists.

    In terms of boosting junction capacity and minimising delays for everybody, what matters more than the safety timings is the question of how many cyclists can cross a junction at the same time rather than separately in drips and drabs. If cyclists can bunch up and wait eight abreast and two deep at a red light (because the cycle lane flares out to allow it, or in an advance stop box), then 16 cyclists can clear the junction together on green and that will be quick. If cyclists wait behind each other or behind cars, that will be slow because the entire queue and not just the front of the queue will move at cyclist speed. Letting cyclists go up to the front and move off together gives motorists a bigger slice of green than they get when every cyclist patiently waits in a different place in the queue. So that’s a conversation on motorist and cyclist behaviour that’s probably well worth having – motorists need to know that it’s in their own interest to cooperate smoothly with cyclists. Discussing the disadvantages of cyclist-friendly intergreens that don’t get cyclists killed strikes me as rather idle in comparison. We clearly need a better guidance note, but we should be able to commission a competent engineer to write one.

    One aspect which is a little more nuanced (and may require input from people other than traffic lights engineers debating among themselves) arises in connection with cycle facilities: if a separated cyclist facility exists and has its own lights, but cyclists are also entitled to use the main carriageway (which they are almost without exception in Ireland), then should the safety timings on the lights on the main part of the carriageway still always have to be calculated for the slowest possible cyclist or can it be assumed that the cyclists on the road are of the kind that can keep up with traffic?

    Another aspect is the balance between safe margins of error and compliance – intergreens that are too long tempt people into breaking lights.

    There may be some scope for improving capacity by tweaking intergreens in individual cases, but the priority should always be safety over capacity, and if that means longer intergreens, then so be it. Mode shift to cycling can create the capacity we need in most places, and where it can’t, Vision Zero should be worth a few seconds to us.

    Green waves are a totally different kettle of fish. Average cyclist speeds and cyclist numbers on routes matter for them, and counting cyclists and gathing opinions is important. 20 km/h on flat routes seems alright to me, but the right balance between routes and modes also matters.

  4. One example of a junction where conflict takes place with pedestrians crossing on a green-man phase is found on Holles St. – Merrion Sq. North – Lr. Mount St. Dublin 2 (an offset junction) where if I am cycling towards Ballsbridge in the bus lane on Merrion Square North and cross the threshold on general ‘green’ phase by the time I reach the pelican-crossing at Lr. Mount St. the pedestrian green-man phase is operational. Pedestrians end up shouting at me for running their green phase.
    Quite simply the clearance time for me to traverse that arm is considerably longer than set for a motor vehicle.
    This is not fair to a cyclist or pedestrian. It is yet another example of our traffic management being designed for motorised free-flow.
    I won’t talk about the traffic signals that fail to detect my bicycle, simply because it is made from an aluminium alloy!

  5. @Mike McKillen If you can think of one or two more junctions like the Holles St. – Merrion Sq. North – Lr. Mount St, maybe you could find a lecturer on the lookout for research projects for engineering students and suggest a research project? It would be interesting to know if those junctions reflect the guidance currently in place accurately and how severely the current timings, the guidance and the real needs of real cyclists diverge.
    If you could offer yourself and a few more cyclists as guinea pigs and already had a locations or three in mind (or even just the one, for a small but interesting project), the research would be as easy to conduct as shooting fish in a barrel. And it sounds like it would be addressing a real and important problem as well as familiarizing the students with the needs of non-motorised road users.


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