Calgary is planning to remove all but 500 of the 1,750 park-and-ride spots at its suburban Anderson light rail station, and gradually convert the space into a mixed-use development. This angers some regular commuters, of course, but local officials have stayed firm. Responding to the concern a couple weeks ago, a local councilman said massive park-and-ride lots simply run counter to the city's growth strategy:
"We have recognized as a city that we have to grow differently — we have to grow up, not out — and the places we start doing that is around transit stations," he said. "The fact that we've surrounded a transit station, which is the ultimate in walkable, with a sea of parking just doesn't make sense any more."
Debates about the merits of park-and-ride facilities crop up in metro areas all over the country. They're not always about tearing down a lot; sometimes they're about deciding whether to build one (or how big to make it) in the first place. And they're not just reserved for big car-oriented suburbs; New York City mayoral candidate Joe Lhota suggested adding park-and-ride to remote subway stops last fall.
As the Calgary situation demonstrates, the wisdom of surrounding transit stations with "seas" of park-and-ride lots may be turning. In theory, park-and-ride seems like a great transportation compromise, converting full-trip drivers into part-trip riders. In practice, the opposite often occurs, with former non-drivers now commuting part of the way by car.
That unexpected practical shift can increase vehicle miles traveled in a metro area, subverting the sustainability goal of transit. (Sustainability isn't transit's only goal, of course, but it's an increasingly important one.) Last year, a Dutch researcher reported that only a quarter of park-and-ride users would ditch transit entirely if the parking lot were removed. The rest now drove part of the time, resulting in a net increase of vehicle kilometers traveled and carbon emissions.
Such findings arguably don't apply to the United States. With fewer alternatives to driving compared to Europe, it's possible that park-and-ride provides a greater benefit to North American metros, in terms of capturing commuters who would otherwise drive all the way to work.
Michael Duncan of Florida State and David Cook of the Virginia Department of Transportation recently studied that possibility in park-and-ride facilities along Charlotte's light rail system, LYNX. Charlotte is a good case study: It's a midsized U.S. metro with a relatively new rail transit system in a region traditionally dominated by car travel. In other words, if park-and-ride reduces driving mileage here, it probably will elsewhere in America.
Determining the effect of park-and-ride on vehicle miles traveled (or, for this study, vehicle kilometers) requires a few steps. First you have to calculate distance driven to and from a light rail station with park-and-ride. Then you have to compare that to hypothetical scenarios in which drivers will no longer use that station if parking were removed. The difference tells you how many miles or kilometers driven the parking lots save.
Duncan and Cook evaluated seven LYNX stations with park-and-ride facilities against 5 rider scenarios ranging from full to no retention. With full retention, all the commuters who used park-and-ride still ride LYNX even without the parking, which means 0 percent drive alone all the way to their destination. With no retention, none of the park-and-ride passengers remain loyal to LYNX, which means 74 percent drive alone all the way (based on pre-LYNX driving habits).
The rider retention rate is key. In the "no retention" scenario, averaged across all seven LYNX stations, the average commuter will drive 14.6 more kilometers (9 miles) — a 69 percent increase in driving. The "full retention" scenario, meanwhile, leads to a decrease of 13.4 kilometers (8.3 miles) per trip — a dip of 64 percent. We chart the average system data below; the tipping point is medium (50 percent) rider retention:
In other words, if you remove park-and-ride and people still ride, there's a huge gain, but if you remove park-and-ride and people just drive, there's a huge loss. More retention might be possible in transit-friendly places like San Francisco or New York. In a place like Charlotte, without many alternatives, Duncan and Cook believe the "none" or "low" scenarios above are most likely. That would result in between 2,000 and 4,000 more vehicle kilometers (1,243 to 2,485 miles) driven a year for a daily commuter, if park-and-ride gets torn down.
Those data seem to recommend against removing park-and-ride in U.S. metros. But they don't tell the whole story. For one thing, there are times, even in the Charlotte system, when removing park-and-ride reduces driving mileage, particularly for stations near the central business district. It's only in remote areas, 11 to 13 kilometers (6.8 to 8 miles) outside the core, where park-and-ride provides a sustainability benefit.
And this also assumes that cities tearing down park-and-ride would put nothing in their place. On the contrary, what Calgary is doing is transforming the parking lot into mixed-use development. As that development fills out over time, more people would live within walking or biking access to the transit station, meaning more people would use the system even in the absence of parking.
In fact, in an unpublished working paper done in conjunction with the LYNX study, Duncan and Cook consider just this scenario. They find that even in Charlotte the prospects look hopeful. Assuming a realistic medium-density for the metro area (75 units per hectacre, for those keeping score at home), replacing the park-and-ride lot with transit-oriented development results in a vehicle kilometer decrease for five of the seven LYNX stations — all but the two most remote stops.
So the case for removing park-and-ride facilities becomes a bit clearer. If the goal is to reduce vehicle miles driven, then mixed-use transit-oriented development with modest parking will be the best way to go closer toward the city, with bigger park-and-ride lots reserved for very remote stations. That's especially true once factoring in the high cost of maintaining a parking lot, the local economic potential of a mixed-use development, and political practicality.
Basically: do what Calgary is doing.