For many cities, the grid of the streets and transit systems were likely laid down long before the buildings grew up around them, thanks to the rigor of planners and engineers who knew best. But as cities transition in ways that challenge the century-old plan, they need new and quick ways to improvise connections between areas of growth. These are known as "desire lines."
Even if you're not familiar with the term, you've seen desire lines in action before. A "desire path" is the term for a trail worn down by foot traffic to create a shorter distance between two points. You'll usually see them slicing through the grass on the quads of college campuses. Desire paths represent user innovation: a faster route through parks or other public spaces. Sometimes, planners take heed of the suggested changes and reconfigure the paved sidewalks, formalizing the recommended changes.
Desire paths through vacant lots in Detroit, by Sweet Juniper
Just like desire paths, desire lines are applied on a slightly larger scale, to urban transit improvements. A desire line would therefore be a new bus route or bike path or ferry line that draws that more direct line between two areas people want to go. A subway system is about building a larger infrastructural network; a desire line connects place to place.
Since the needs of residents change so quickly, cities are looking for quick and affordable ways to connect the dots between like-minded communities and similar economic prospects. Lately, to make this kind of connection with good branding, positive urban vibes, and a minimal infrastructural footprint, streetcars are being employed to travel those desire lines.
One great example is a New York City streetcar, the idea of urban planner Alex Garvin, who proposed such a line 10 years ago. A Brooklyn-to-Queens trolley would start at Ikea (where else?) and travel through famously transit-deprived Red Hook, before rolling along the Brooklyn waterfront all the way to Astoria, Queens.
Along the way, it would help to lace together existing train and ferry connections as well as parks and recreation spaces, yet it would also offer the first efficient and sensible way to get from, say, Williamsburg to DUMBO.
L.A.'s downtown has a similar challenge. While it's well-served by transit, the major cultural attractions are spread out over a few square miles, and sometimes there's no easy or direct route between them.
A similar streetcar proposal hopes to link areas of downtown that are frequented by both residents and tourists—Staples Center, Disney Hall, etc.—in a way that enhances pedestrian life and almost becomes another tourist attraction itself. It's basically a ride.
The Grove's trolley at Christmas, photo by Paul Stumpr
Where desire lines can get really interesting is when the destinations themselves start to pay for and develop these short transit lines. Rick Caruso, the developer of The Grove, a large Fantasyland-esque mall in the heart of L.A., has expressed that he would like to take the mall's trolley (which runs back and forth on less than a mile of track) and extend it out into the streets. His plan would be a single transit loop that connected The Grove with the nearby Beverly Center and Los Angeles County Museum—all places he knows that his patrons already visit on a single trip.
Subways and light rail projects are expensive and onerous to take on, requiring not only the heavy construction of tunneling and laying rail, but also the legal implications of navigating preferred routes and right-of-ways. The beauty of desire lines are not only their light touch, but also the unique multimodal options they can introduce to a city: gondolas stringing up hillsides, ferries chugging between two waterfront neighborhoods. Imagine cities shifting away from the bulky pre-determined routes for cars in favor of diagonal bike paths and pedestrian cut-throughs.
With today's data collection and ability to study traffic patterns, it's much easier for cities to figure out where their residents want to go. Instead of massive capital campaigns, expect to see a lot more nimble "desire line" transit knitting together our cities. [New York Times, Vox, Curbed LA]