Friday, September 13, 2013

Bridging highways and rail lines for safety

View Crossings of I-94 vs. ex-NP line in St. Paul in a larger map

The construction of Interstate 94 through St. Paul is often seen as a black mark on the city's history, but there was one fairly positive outcome from the planning processes of the time—there is a very regular interval of pedestrian connections across the freeway, with bridges almost every quarter-mile from the city's downtown to the western border with Minneapolis. Most of the crossings carry a mix of traffic, but some are exclusively built as bike/pedestrian bridges. It's the most consistent stretch of cross-highway connections I've found anywhere in the Twin Cities.

I don't really enjoy crossing I-94 on foot or by bike, but it is easy to find access points. That's in sharp contrast to my own neighborhood about two miles to the north, where there is much poorer connectivity across a railroad line that is more than half a century older than the Interstate. I was starkly reminded of the problem last month when a 9-year-old boy, Marshawn Farr-Robinson, fell from a moving train which chopped his feet off at the ankles. That incident happened at an illegal crossing near Ivy Avenue and Farrington Street (shown with a red marker on my map above).

Minnesota Public Radio reported that the site lacked a required fence, but is sealing up the railroad corridor at this spot really the right response? In order to go the one-block distance from the corner of Farrington and Ivy Ave north to Farrington and Cottage Ave, a person could walk directly across the tracks and get there in about 3 minutes (assuming there wasn't a stopped or moving train blocking the path). Or, that person might decide to take the shortest legal route by going over to Dale Street and doubling back: 7/8ths of a mile, taking about 17 minutes. Even if you had to wait 10 minutes for a train to pass, it'd still be easier to go straight across the tracks, so that's what people do.

I live near an illegal crossing along that same rail line at Hamline Avenue, which people use to get between the Bandana Square area of Energy Park and the Como Park neighborhood just to the north. There's a fence there, but a hole has been cut in it for many years. It periodically gets repaired, but is opened up again just as quickly.

What is the right distance to have between crossings of a man-made or natural boundary—a highway, a rail line, or a river? You can go somewhat overboard, like with the old Milwaukee Road corridor in south Minneapolis, now the Midtown Greenway—that gets up to nearly 16 crossings per mile, or one for nearly every short side of a block. In St. Paul, city blocks are mostly oriented with their long sides running east-west, so the bridges over I-94 are roughly one every two blocks.

We can take a cue from the "desire paths" which cross the railroad tracks today: From visual inspection of the line on the ground and via my favorite mapping sites, it appears that they show up pretty consistently about every 1/2-mile. There are a few oddballs, like a path that has been cut immediately east of Snelling Avenue, but that's partly there because everybody hates using the on-ramps to walk into and out of the Energy Park neighborhood. A spot like Snelling might only need to have some stairways cut into the existing embankments to make a safer crossing, while other places would need bridges or pedestrian underpasses. Those cost a few million dollars each, but with the federal government putting the value of a human life at $7 to $8 million, it's pretty easy to argue in favor of adding new bridges rather than new fences as the best way to make living around railroad lines safer.