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Traffic Modelling

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What design assessments and traffic modelling were carried out in regard to banning right turns from London Road onto Leith Walk, and what were the outputs?

Proposals for the redesign of the Leith Walk / London Road junction were previously considered as part of Leith Walk Phase 6.  The existing layout has a very large footprint and acts as a barrier to pedestrian movement.  In developing a new design, a key objective was to reduce the amount of space given to road traffic, while increasing the area given to active travel and an improved public realm.  A full-width pedestrian/cycle crossing at London Road was considered desirable to improve walking and cycling connectivity to and from Leith Walk.  In order to accommodate these requirements, it was necessary to simplify the traffic signal staging by banning the right turn from London Road towards Leith Walk northbound and Annandale Street.

In the morning peak, the traffic modelling indicates that approximately 123 vehicles make the right turn from London Road to Leith Walk, of which only 24 are considered strategic and the remaining attributed to local trips.  When the right turn is banned, virtually no vehicles travel from London Road to Leith Walk via Picardy Place.  However, if a vehicle was to undertake this manoeuvre then there will be an additional travel time of approximately 84 seconds.

A significant proportion of the vehicles that turn right from London Road to Leith Walk travel along Annandale Street / East London Street to Broughton.  Closing this turn provides an added benefit in that it prevents rat running along these streets.  St Mary’s Primary School is located on East London Street and banning this right turn results in approximately 180 fewer vehicles an hour passing this school during the morning peak.

Traffic modelling further indicates that currently, it takes approximately 80 seconds to travel to the roundabout at London Street / Broughton Street via Picardy Place and 113 seconds via Annandale Street / East London Street.  Once the right turn ban is imposed, the travel time to the London Street / Broughton Street roundabout via the redesigned Picardy Place is approximately 91 seconds.

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What traffic modelling was carried out in regard to banning left turns from Leith Walk to London Road?

The London Road junction is a key junction for the east of the city and will also play a crucial role in the successful operation of the trams. Following traffic modelling of the junction, it became clear that maintaining the left-hand turn when the tram was operational would increase congestion at the junction and adversely affect the tram timetabling. The junction would not be able to work effectively.
In the morning peak (08:00-09:00), 52 vehicles turn left from Leith Walk with a further 27 turning from Elm Row and in the evening peak (17:00-18:00) it is 102 plus 32 from Elm Row. With the subsequent closure of Montgomery Street onto Elm Row, this will reduce the number of vehicles looking to make this manoeuvre onto London Road.
Banning the left-hand turn also allows the project to deliver an improved pedestrian and cycling experience at the junction. A single-stage crossing point will be installed on London Road for pedestrians and the dedicated cycle lane will connect with Picardy Place and beyond.

There are a few options available to drivers. They can either go straight on, up to Picardy Place and then back down before filtering into two lanes that will allow the right-hand turn onto London Road. The increase in journey time would be between 1 – 3 minutes.
Alternatively, they will come via Broughton Street, through Picardy Place and use the two lanes that will allow the right-hand turn onto London Road as described above.

75% of the traffic currently making the left-hand turn is coming from Annandale Street. By removing the left-hand turn, traffic will be encouraged to use main arterial routes which is consistent with the Council’s plan to minimise traffic on smaller roads.
It should be noted that Montgomery Street and Brunswick Road (heading east) will no longer be accessible for traffic following the construction of the trams.
Monitoring of other roads such as Albert Street and Dalmeny Street will take place but the displacement onto these roads is expected to be minimal.
Tram will also result in less traffic using McDonald Road and Pilrig Street due to the reduction in green traffic light time.

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What traffic modelling was carried out in regard to the proposal to divert all Leith-bound traffic to Easter Road and Bonnington Road during the construction phase, and what were the outputs?

Traffic modelling of both morning and evening peak periods has been undertaken for these diversion routes.

With Leith Walk operating city-bound only, analysis shows that traffic volumes on Easter Road Leith-bound increase from an approximate average of 400 to 600 vehicles per hour in the morning peak.  In the evening peak on Easter Road, traffic flows increase from around 350 to 600 vehicles per hour.  To accommodate this increase in traffic flow junction improvements will be carried out at the Duke Street roundabout.

Leith-bound traffic on Bonnington Road increases from an approximate average of 300 to 400 vehicles per hour in the morning peak.  In the evening peak on Bonnington Road, traffic flows increase from an average of 280 to 400 vehicles per hour.

What traffic modelling has been carried out in regard to the banning of general traffic from entering Constitution Street from Leith Walk?  In the same vein by removing general traffic from the South End of Constitution Street what effect does this have on traffic displacement, specifically considering Duncan Place and Queen Charlotte Street?

Detailed transport modelling of the impacts of this change has been undertaken.

In the morning peak, approximately 200 vehicles per hour travel Leith bound on Constitution Street and 250 vehicles city bound.  With Constitution Street closed to general traffic, approximately 40 extra vehicles per hour use Duncan Place Leith bound and 40 extra vehicles per hour use Henderson Street.  The remaining 120 vehicles are more widely displaced, using alternative routes across the road network.

In the opposite citybound direction, with Constitution Street closed, approximately 65 extra vehicles per hour use Duncan Place, 115 extra vehicles use Henderson Street and the remaining 70 vehicles are displaced evenly around the road network.  To alleviate this increase on Duncan Place the project team are currently appraising traffic calming measures within the area.

Modelling indicates that Queen Charlotte Street will also see a small reduction in traffic in both directions as a result of Constitution Street being closed to general traffic.

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The design of the lower half of Leith Walk reduces road capacity and introduces a signalised release system for the tram at Balfour Street.  What effect does this have on car/traffic journey times on Leith Walk and what effect does this design have on traffic displacement?

Traffic flows on Leith Walk are reduced in both directions as a result of the implementation of tram and the closure of Constitution Street to general traffic.  Between Balfour Street and the Foot of the Walk morning peak, hourly traffic volumes reduce by approximately 100-200 vehicles Leith-bound and 250-400 vehicles city bound.

On the parallel section of Easter Road, traffic volumes increase by approximately 20-80 vehicles Leith bound and 10-150 vehicles city bound.  Traffic volumes on the parallel section of Bonnington Road increase by approximately 10-25 vehicles Leith bound and 20-150 vehicles city bound.

As along other sections of the route, traffic signals will be coordinated to provide a tram green wave so that, under normal circumstances, trams travel between stops without delay.  Over the lower section of Leith Walk, northbound trams will be released from the Balfour Street stop ahead of other vehicles, helping to keep a clear route ahead.  City-bound trams leave the Foot of Leith Walk stop in their own signal stage which again helps provide a clear path towards Balfour Street.

In the morning peak, the average modelled car journey time on Leith Walk between Pilrig Street and the Foot of the Walk is 1 minute 10 seconds.  This increases to approximately 2 minutes 40 seconds with trams in place.

City-bound, existing car journey times are approximately 1 minute 50 seconds, and these are forecast to increase to 2 minutes 35 seconds once the scheme is in place.

In addition to the signalised release system, increased journey times are a result of the additional signalised junctions at Manderston Street and Lorne Street, which are required as part of the tram project.

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By stopping up Montgomery Street entirely what impact does this have on traffic displacement on surrounding streets, including Brunswick Road?

With the right turn from London Road to Leith Walk north prohibited and Montgomery Street stopped up entirely, there is the potential for east to northbound traffic to be displaced towards Brunswick Road.

Traffic modelling indicates that, under this scenario, an extra 100 vehicles per hour will use Brunswick Street westbound in the morning peak.  To compensate, it is to make Brunswick Road westbound only at Leith Walk with eastbound traffic displaced to London Road and Albert St.  Widened footway and additional cycling facilities will be provided from Tesco at Leith Walk towards Dicksonfield.

Traffic modelling indicates that there are approximately 240 vehicles travelling eastbound on Brunswick Street and Montgomery Street in the morning peak; the majority of these will be displaced to London Road once Brunswick Road is made westbound only and Montgomery Street is stopped up entirely.

What effect does the tram stop have at Bernard Street on the operation of the Bernard St / Baltic St / Constitution St junction?

The Shore tram stop is in close proximity to the Bernard St / Baltic St / Constitution St junction. It is unusual in that it is the only stop where general traffic is permitted in the lane adjacent to the platform.

The closure of Constitution Street to general traffic at Leith Walk results in a reduction in through traffic on the approach to the Bernard Street / Baltic Street / Constitution Street junction.  To allow Newhaven-bound trams to operate efficiently, it is that the Constitution St arm is double cycled; meaning the first stage operates to flush out traffic in advance of a tram approaching The Shore stop while the second stage, which runs approximately 35 seconds later, releases trams towards Newhaven.

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