The image below presents a ‘Melbourne Shopping Street’ reference design, where cars share a lane with trams but are prevented from slowing them down. Parking is re-located to the first 5-10 bays on each side street, with shoppers guided to vacant bays using sensors. Space is re-allocated to bicycle lanes that include level access tram stops. This article describes how the reference design was derived from ‘Safe System’ and ‘Movement and Place’ design methodologies.
Introduction
Melbourne’s shopping & tram streets typically have a width of 20 metres from building to building. There is not enough space to build a separate lane for people using each travel mode, including walking, cycling, riding in a tram, driving and parking. The street space is contested. To determine how the available street space should be allocated, designs should be assessed using both ‘Safe System’ and ‘Movement and Place’ methodologies.
Safe System
‘Safe System’ is a design methodology used by governments around the world who understand that their primary mission is to protect the public. It is based on the principles that road users are fallible and will make mistakes but that no one should be killed or seriously injured when a crash occurs. The Safe System approach is a foundation principle of Australia’s National Road Safety Strategy and Victoria’s Towards Zero strategy.
A Safe System assessment shows which street designs are permissible and which are not. An assessment includes identifying the hazards and quantifying the risks. An example of a hazard is being struck by a car when disembarking from a tram; or colliding with a suddenly opened car door when cycling along the street. Both of these hazards impose the risk of serious injury or death.
From July 2018 in Victoria, a Safe System assessment must be conducted for all major road projects. Prior to this date, a novel type of level access tram stop was constructed on Bridge Road in Richmond. The street retained two lanes of traffic in each direction, which meant that cars drove over the level access tram stop.
This design fails the Safe System approach. People disembarking from the tram during clearway times could be struck by a car, and people cycling during non-clearway times could collide with a suddenly opened car door.
In contrast, the ‘Melbourne Shopping Street’ reference design complies with the Safe System approach because it eliminates those two hazards. The reference design does introduce a different hazard, that of a person disembarking from the tram being struck by a person on a bicycle. However this hazard does not impose a risk of serious injury or death, because the kinetic energy of a person on a bicycle is much lower than that of a car. In addition, the reference design eliminates the hazard of a cyclist colliding with a suddenly opened car door, because the parking has been re-located to side streets.
Movement and Place
‘Movement and Place’ is an evolution of the SmartRoads framework that VicRoads uses to manage the competing interests for limited street space. It recognises that a street can perform two functions: as a movement conduit and a place, a destination in its own right.
Melbourne’s shopping streets are an ideal case study for the ‘Movement and Place’ framework because they deliver both functions: people use them to travel around greater Melbourne, as well as travel to them to shop and socialise. The beauty of the ‘Melbourne Shopping Street’ reference design is that it ranks highly on both Movement and Place – proving that the two are not mutually exclusive.
A shopping street is self-evidently a Place, a destination where locals go to shop, eat, meet and socialise. As our population density increases, shops cluster along tram corridors because that is where the people are. Over time, shopping precincts extend along the full length of tram lines, adding more and varied destinations to the Place. The ‘Melbourne Shopping Street’ reference design improves the Place rating of the street because it offers wider footpaths, making it easier to walk along the street from shop to shop, or to enjoy expanded footpath seating. It also visually integrates the two sides of the street and increases passive surveillance opportunities, as parked cars are no longer blocking views from the footpath towards and across the street.
Compared with the status quo, the ‘Melbourne Shopping Street’ reference design also improves the Movement rating of the street because it moves more people during peak hour. A high quality cycleway can accomodate 4,600 people per hour, more than double the 1,900 vehicles per hour in a traffic lane. Similarly, a free running tram can carry 2,640 people per hour, also more than a vehicle lane [Reference: Victorian Cycling Strategy 2018-28].
A key element of the ‘Melbourne Shopping Street’ reference design is that cars share a lane with trams, but do not slow them down. To achieve a high Movement ranking, trams need to travel almost unimpeded. This can be achieved even if the lane is shared with cars. The solution contains two elements: prevent cars from overtaking trams and thereby filling the lane in front of the tram; and using smart traffic light sequencing to clear intersections as trams approach.
With the ‘Melbourne Shopping Street’ reference design, trams will travel almost unimpeded from stop to stop. Cars will follow trams and travel at the tram speed. The overall speed of the street is determined by the tram, not cars, because it delivers the maximum possible Movement rating. Vehicles can still use the shopping street and access all destinations, their only compromise is to accept the travel speed that maximises total Movement.
Overall, the ‘Melbourne Shopping Street’ reference design maximises the people carrying capacity, or Movement rating, of the available space. The most geometrically efficient modes (walking, cycling and trams) are provided enough space to function effectively. Any other street design, such as without bicycle lanes, without trams, or without either, delivers a worse or lower Movement rating.
Conclusion
The ‘Melbourne Shopping Street’ reference design has been assessed using both ‘Safe System’ and ‘Movement and Place’ design methodologies. The design complies with Safe System principles and delivers high ratings for both Movement and Place. Any other street design, such as without bicycle lanes, without trams, or without either, delivers a worse or lower Movement rating. Therefore, the ‘Melbourne Shopping Street’ reference design is the optimum design for Melbourne’s 20 metre wide tram-based shopping streets.
Originally published on 21st November 2018 as an article on LinkedIn.