Reallocating Street Space and Signal Time

Traffic Signal in Sydney, June 2020 Sydney

Street Space Reallocation

The opening of the final pieces of the WestConnex Motorway in Sydney presents opportunities for street space reallocation. By diverting traffic away from local roads and onto the motorway, the project frees up urban space that was previously dedicated to car traffic. That space should be reallocated to:

  1. Active Transport Infrastructure: Reduced traffic provides an opportunity to develop more infrastructure for active transport modes like cycling and walking. This could include dedicated bicycle lanes, widened footpaths, pedestrian plazas, and improved crosswalks.
  2. Green Spaces: Unused or underutilized street space can be transformed into green spaces such as parks, urban gardens, or tree-lined avenues. These changes would not only improve the aesthetics of the city but also have health and environmental benefits.
  3. Public Transit Priority: Less road congestion lets us allocate more street space to public transport. Dedicated bus lanes or tram tracks could be installed, potentially improving the efficiency and attractiveness of public transit.
  4. Outdoor Dining and Retail Spaces: In the post-COVID era, outdoor dining and retail spaces have gained popularity. Footpaths or parking lanes can be transformed into commercial spaces that allow businesses to serve more customers while also activating the street scene.
  5. Street Beautification and Placemaking: Reducing the dominance of cars on streets can contribute to a more pleasant urban environment. Opportunities exist for more public art, attractive lighting, or unique pavement treatments that help to create distinct, enjoyable places.

The excellent new City of Sydney Access Strategy and Action Plan understands this, and is large step forward which needs to be implemented. [Feedback is due August 7, 2023]

Signal Time Reallocation

Sydney Coordinated Adaptive Traffic System (SCATS) is a traffic management system used not just in Sydney, but across the globe. This system focuses on optimizing traffic flow, reducing congestion, and improving road safety through real-time adaptive signal control. It is designed to be highly responsive to the actual traffic demand at each signalized intersection.

However, with growing urbanization and increasing awareness about environmental sustainability, there has been a shift in focus towards prioritizing pedestrians and public transport over private vehicles. Pedestrian delay reduces walk accessibility, and thus reduces walking. Sydney aims to enhance its pedestrian-friendly spaces and public transport systems. Signal Time Reallocation can aid in achieving a number of broader goals like liveability, sustainability, public transport efficiency, safety, and equity.

One reason pedestrians are not prioritised is that pedestrians are not systematically counted at intersections — and as we all know, that which isn’t counted, doesn’t count. The basic technology to do so lies in the pedestrian actuator itself, already installed at every intersection. But if that is too simple and inexpensive, government can purchase sophisticated pedestrian detection technologies. In either case, by knowing the number of pedestrians, the system should better adapt to pedestrian demand in real-time. SCATS already uses detectors to measure vehicle demand, and doing so for pedestrians is the logical next step. SCATS should also make this Open Data, there are no actual privacy concerns. Citizen Scienceshould not be required to estimate traffic signal timings when we have actual well-funded (dare I say profitable, SCATS is sold globally) governmental units capable of, and charged with, doing this.

Traffic signal timings play a crucial role in determining the pedestrian experience at intersections. There are several ways that these timings can be adjusted to increase pedestrian time and reduce pedestrian delay. These strategies should be implemented in conjunction with broader pedestrian-friendly policies, such as lowering speed limits, changing road rules to make every intersection a crosswalk, and improving pedestrian infrastructure with devices like raised pedestrian crossings. These include:

  1. Extend Walk Times: Increasing the duration of the “walk” signal gives pedestrians the maximum rather than the minimum time to cross, which is essential (and the only ethical choice, really) in a world with slower pedestrians like the elderly or those with disabilities.
  2. Reduce Cycle Length: The cycle length is the time it takes for the signals to go through one full rotation (from green to yellow to red and back to green). Shorter cycle lengths mean pedestrians have to wait less time for the next walk signal.
  3. Early Start for Pedestrians: Also known as a “leading pedestrian interval” (LPI), this gives pedestrians a head start before vehicles are allowed to move. It makes pedestrians more visible and reduces conflicts with turning vehicles.
  4. Pedestrian Scramble: Also known as a “Barnes Dance”, this is a phase where all vehicular traffic is stopped, and pedestrians can cross in all directions, including diagonally. This eliminates conflicts with vehicles but requires more “all red” time, which could increase delay for vehicles.
  5. Pedestrian Activation: Some signals require pedestrians to push a button to activate the walk signal. Every phase should automatically permit pedestrian crossings. The actuators should be repurposed to call the signal, getting it change earlier, rather than merely notifying the controller that there is a pedestrian present. 
  6. Countdown Timers: While this does not increase pedestrian time or reduce delay, it does provide information that allows pedestrians to make better decisions about whether to start crossing.
  7. Adaptive Signal Control Technology: This uses sensors to detect pedestrian presence and adjusts signal timings in real-time based on actual demand. It’s particularly useful during off-peak hours when pedestrian volumes can be variable.
  8. Remove Slip Lanes: Slip lanes allow vehicles to make right turns at higher speeds but can be dangerous for pedestrians. Removing them means more space for pedestrians and less conflict with vehicles.

Similarly, there are improvements for Public Transport. 

  1. Transit Signal Priority: The average transit vehicle carries many more people than the average car. It should be given priority from both equity and efficiency grounds. In short this means implementing “transit signal priority” (TSP) measures that give buses or trams priority at intersections.

Jointly, street space reallocation and signal time reallocation can reshape the city, they are twin pillars on which a successful pedestrian strategy lies.

Service Changes Don't Push the Button Pedestrian Crossing Now Automated Wait for Green Signal Before Crossing For More Information
Service Changes Don’t Push the Button Pedestrian Crossing Now Automated Wait for Green Signal Before Crossing For More Information