A key point is that minutes, and even seconds, can matter. When the goal is to maximize the opportunities available in a short window of time, shaving off a few seconds here and there adds up to minutes, and saving those minutes can have an outsized impact on overall accessibility. To illustrate, consider Figure 1, which shows the potential area a person could access from a central point if they travel for 10, 20 or 30 minutes. Note that each additional 10 minutes of travel opens up a much larger area and provides access to many more locations. The area of the accessibility ring from 20 to 30 minutes (grey) is much larger than from 10 to 20 minutes (cardinal) and even larger than 0 to 10 minutes (gold).
Figure 1. Accessibility rings
Now imagine that a traveler routinely experiences a 10-minute delay in what would otherwise be a 30-minute trip. That delay costs them more than half of their accessibility, meaning it deprives them not only of time but also of significant opportunities. Figure 2 extends this point and shows that the relationship between travel delay and lost accessibility is non-linear, which means that the first few minutes of delay count more, and the impact diminishes as the delay gets longer. A five-minute delay reduces trip accessibility by 30 percent, but a 10-minute delay costs travelers 50, not 60, percent. The initial minutes of delay cost more. This point brings us back to the importance of seemingly-small decisions.
Figure 2. The estimate of percent accessibility loss
Improving Access to Train Platforms
A simple example of how small decisions can improve overall regional accessibility can be found on the boarding platforms of Sydney Trains, the Sydney region’s 813 km (505-mile) commuter rail system.
Sydney Trains is one of the best commuter rail systems in the English-speaking world, providing high-frequency service from many suburbs to central Sydney. However, 44 of its 175 stations have entrances at only one end of the platform. A traveler approaching from the other end of the platform must walk alongside the station for the full length of the platform, which — given the length of trains — usually takes two minutes. Some unfortunate passengers travel between two stations with gates on only one end of each platform, and a quarter of them face situations where the gates are on the “wrong” end of both platforms. Because minutes matter, this design exacts a heavy toll in accessibility, and probably a heavy toll in ridership. A long history of research, along with a simple dose of common sense, tells us that people who live closer to transit are more likely to use it than those living farther away. People who can see the platform but not get to it (because it has no entrance near them) for all intents and purposes live further away. They have less access and ride less, and this results from nothing but the mismatch of entry and exit locations at the train stations.
Figure 3a provides a real-world example of this problem, by mapping access to Erskineville station, one of the most extreme cases of accessibility loss in the Sydney Trains system. The figure shows five-, 10-, and 15-minute bands of walking time around the station. In 2016, about 1,400 people lived within a five-minute walk (about a quarter-mile) of the station platform.
This number would be larger, but many people live or work on the south end of the platform, which is near a number of large apartment blocks. Unfortunately, the station’s only entrance is on the north end. If a southern entrance were added, the number of residents who live five minutes away would increase by 89 percent (Figure 3b). This increase in accessibility should translate into more riders, as well as increased land value and higher real estate tax revenue. Indeed, the second entrance could add enough ridership, and new revenue, to pay for itself.
Erskineville is just one example. Similar interventions could be made for most stations, in Sydney or beyond, that have comparable configurations. Misaligned station entrances are low-hanging fruit that cities can easily pick. The costs are low, the gains are large, and the improvements can be made immediately.
Accessibility comparisons at Erskineville Station before and after potential new station entrance
Figure 3a. Map
Figure 3b. Changes in population and jobs access
Encouraging Bus Rapid Transit
A second example of gaining lots of regional accessibility by saving just a few minutes comes from the Minneapolis-St. Paul A Line, a rapid bus service that opened in 2016. The first rapid bus line of the region’s transit network, the A Line operates from the suburban Rosedale area and connects to both lines of the region’s light rail system. The line is effective, in part, because several seemingly small features allow it to save a few seconds of time for each passenger at each stop, compared to a conventional bus line:
- Prepaid fares: Passengers tap a fare card on the platform before boarding the bus, rather than line up at the front of the bus to tap-in or pay in cash. This saves 1.5–6.0 seconds per passenger.
- All-door boarding: Since they have already paid their fare, passengers can board at any door, not just the front. This cuts the overall boarding time in half.
- Fewer stops: Conventional buses stop roughly every eighth of a mile. The A Line stops every half-mile. Fewer stops result in less time spent slowing down, waiting, and then picking up speed.
A few seconds per passenger, when there are many passengers, adds up to a lot of time saved. Combined, these interventions result in more and quicker trips, even with the same number of buses and hours of driver time. Bus service thus becomes more productive. But does access increase? For the most part, yes. Figure 4 maps neighborhoods near the A Line, and shows whether they gain access to jobs (green) or lose it–because people there now need to walk farther to reach stations (yellow). Most people in the area come out ahead. They have longer walks to stations, but the faster and more frequent buses compensate for that and let people reach more locations in the same overall travel time. Overall, the rapid bus configuration increased job accessibility by 5 percent for local residents. As was the case with Sydney Trains, nothing is particularly unique about this situation. Bus networks in many cities could apply these lessons and make small changes that yield large returns.
Figure 4. Change in number of jobs within 30 minutes by transit
Rethinking Traffic Signals
Here is a final example: traffic signals. Everyone, from a young age, is familiar with traffic signals. But cities installed traffic signals to help drivers, not pedestrians (pedestrians, after all, even in crowds, can navigate around each other without collisions). As traffic proliferated over the last century, signals gave increasing priority to cars, and pedestrian conditions worsened. Pedestrian travel quality has deteriorated because traffic signal engineers have focused more on limiting vehicle delay rather than improving pedestrian accessibility.