As Orphan Road brought up in their own great post on the same subject, light rail skeptics are commonly cite “transit share” as a way of dismissing serious investment in our transit infrastructure. But what is “transit share”? Well, first we have to see what it’s a “share” of: the total amount of trips in the region. Walking down the block to the grocery store is a trip. Taking the bus to work is a trip. Bicycling to Pike Place Market is a trip. The transit share is the percentage of all trips made by transit.
I dismiss this measure as a distraction in the headline. And here’s why: evaluating every trip with equal weight is not meaningful. There are work trips and non-work trips. Unsurprisingly, non-work trips have a very low transit share (see the graph to the right) but they also have a much higher walk/bike and carpool shares. These non-work trips drag the over-all transit share down, allowed a significant investment in light rail and bus service to be spun as a waste.
But non-work trips are the trips made during off peak times where congestion is minimal. Congestion is the largest motivator of highway spending, and when transit provides a sensible alternative to driving to work alone the region can not only save money but help the planet at the same time. Note how 75% of work trips are in single-occupancy vehicles. I call that “low-hanging fruit.”
Besides congestion, non-work trips differ substantially from work trips in length. According to the PSRC, work trips are expected to be more than two and half times in length than non-work ones by 2040 (around 13 miles compared to around 5 miles). Those single-occupancy vehicles driving for longer distances in congestion for work trips represent the largest collective emitter of CO2 in our region.
So, work trips are where the congestion is, they’re where the single-occupancy drivers are, and they’re where the length is. Just like when the highway lobby talks about congestion they mean during peak hours, so should an honest conversation about transit reflect its peak use. As Orphan Road points out, one alternative for the region’s 2040 plans, which focuses heavily on light rail investment, nearly doubles the transit share of work trips to 19%. That’s the number that matters.
(Once again, this post was inspired by a blog entry by our friends at Orphan Road. Be sure to read their original report.)