It takes two to three minutes to drive one mile north east from Tibbett’s Corner to the junction of West Hill (A3) and the Upper Richmond Road (South Circular). The traffic lights at this junction show a green signal for fifty seconds of every hundred seconds, allowing twenty to thirty vehicles on West Hill to pass every hundred seconds
During peak times, the volume of A3 traffic arriving at Tibbett’s Corner surpasses the volume moving through the traffic lights at the junction with the South Circular. West Hill traffic is slowed to almost a standstill with traffic queuing back towards Tibbett’s Corner. The three to four minute journey time is increases to around sixteen minutes. There’s a constant line of HGVs, coaches, lorries, trucks and cars, each accelerating and braking around forty times and idling for around twelve minutes.
Every acceleration of a diesel vehicle releases carcinogenic fumes into the air. Every time a vehicle is stopped, tiny bits of metal, rubber and oil are released from the brake pads, tires and suspension. Idling vehicles can produce twice the emissions of a moving vehicle.
The number of times each vehicle accelerates and brakes can be reduced if traffic lights were optimised to hold vehicles stationary (for two to three minutes) until the section of road ahead is clear. This would also provide opportunities for drivers to switch off their vehicle engine rather than idle.
On this one mile section of West Hill there’s a nursery, a hospital, residential apartments, houses, large council estates, a care home for the elderly and a school with over 1,100 children. During the morning peak, thousands of people travel along West Hill breathing air that may exceed EU and UK hourly legal limits for NO2.
I believe that a significant reduction in vehicle emissions is achievable if we reduce start-stop-idling on West Hill.
Managing West Hill’s traffic lights
The action proposed below does not affect the traffic light timings at the junction of West Hill and the South Circular.
There are two other sets of traffic lights along this one mile section of West Hill that could be optimised; Portinscale Road / West Hill Road and another near the entrance to the Royal Hospital for Neuro Disability.
A third traffic light would be needed near Putney Heath Lane, just after the bottleneck where three lanes of A3 traffic converge into a single lane.
Holding north east traffic at these traffic lights (two to three minutes) until the section of road ahead is clear, would reduce the number of times vehicles accelerate and brake by over 70%.
Holding north east traffic at these traffic lights for two to three minutes, would provide drivers with clear opportunities to switch off their vehicle engines rather than idle. If average vehicle engine restart is estimated to be equivalent to thirty seconds worth of idling, emissions due to idling could be reduced by over 70%.
Managing driver behaviour
Restricting peak time access to West Hill North East lane from the five side roads would prevent ‘rat running’.
Driver facing countdown timers on traffic lights and lampposts along West Hill would inform drivers of the time remaining till a green light.
A 20mph speed limit would help maintain a steady flow of traffic on the clear section of road ahead, reduce vehicle emissions and improve safety for hundreds of children who cross West Hill every morning.
South West lane
Any changes must not delay south west traffic on West Hill. Any delays to traffic on the south west lane increases vehicle idling all the way back to Wandsworth High Street. The proposed traffic light optimisation would at times hold north east traffic behind a red signal whilst showing a green signal to south west traffic.
The following actions can improve south west traffic flow, allowing the single lane of traffic to quickly reach the three lanes at the top of West Hill.
Traffic on West Hill’s south west lane is regularly delayed by vehicles waiting to turn right onto Portinscale Road. Drivers seeking to access Portinscale Road can do so via Keswick Road, off the Upper Richmond Road.
The 170 bus has three scheduled stops on the south west lane of West Hill. Each time a bus stops it completely blocks the single lane of traffic for between ten to sixty seconds. The knock on effect is significant with each bus forcing hundreds of vehicles to stop idle and accelerate multiple times. ‘Shallow’ bus stop bays would allow vehicles to overtake the stationary bus whilst still making it easy for the bus to swiftly re-join the traffic. This would significantly improve South West traffic flow, allowing thousands of vehicles to quickly reach the three almost empty lanes at the top of the hill and significantly reduce idling time.
TfL
As West Hill is a TfL managed road, I have contacted TfL’s Project and Programme Sponsorship. They have since conducted a site visit and said that they will commission their in-house design team to “look at the options that they have for the area and see if they can come up with some innovative solutions”.
TfL didn’t say that my solution wouldn’t work, just that they would rather look at their own options and find their own solution. TfL made it clear that with the number of competing projects and priorities, it will likely take some time for TfL to focus on solutions for West Hill.
They did however agree to request the Department for Transport provide some new ‘keep clear’ types of road markings to discourage drivers from idling in front of kerbside bus stop shelters.
Wandsworth Council
I’ve been liaising with Wandsworth Council to co-locate AQMesh monitors with the reference station on Putney High Street and they have been very supportive of my efforts to monitor hourly NO2 levels on (Putney High Street’s dirty big sister) West Hill. I have requested that they engage TfL to progress solutions for West Hill and to ask their engineers to undertake their own feasibility study to see whether my proposed solutions would significantly reduce vehicle emissions.
I’ve raised the need for a living green shield between the idling traffic on West Hill and the school with over 1100 children (image above). I’ve also asked Wandsworth Council to request the Department for Transport provide ‘keep clear’ type road markings for use at kerbside bus shelters on roads manged by Wandsworth Council.
Your support
The solutions for West Hill may also help reduce traffic pollution and public exposure in other areas of the UK that have high NO2 levels due to start-stop idling traffic. We should be moving quickly to test and share ideas that could significantly reduce vehicle emissions and public exposure to harmful levels of air pollution.
Please show your support by signing our petitions asking the Mayor of London to pilot our Rush Hour Pollution Solution on this one mile section of West Hill and for keep clear road markings at kerbside bus stop shelters.
With your help we can ensure vehicle emissions are kept to a minimum at the time millions of people travel to work, college, schools and nurseries on London’s busiest roads.
David
