Another in the series by Clark Derry-Williams of Sightline: Dude, Where are My Cars? This one is particularly prescient, given the imminent opening of the Port Mann Bridge on this side of the border – but more importantly, the determination of TransLink to proceed with designing a six-lane replacement of the Pattullo Bridge, paid for by tolls.
Here’s a blast from the past: The early forecasts from the Washington State Department of Transportation'(WSDOT), dating from 2002, of traffic on the SR-520 floating bridge after the start of tolling.
Depending on the tolling scenario, WSDOT predicted that the floating bridge would carry between 90,000 and 98,000 cars per day in the first year of tolling, down from a projected baseline of 118,000 cars per day with no tolling.
But the reality for January through June, the first six months of tolling: an average of 63,500 cars on weekdays, down from a baseline of 101,100 weekday cars the prior fall. When you include weekends as well, the trends are even more striking, with a dip to fewer than 57,000 cars per day.
WSDOT’s early forecasts were doubly mistaken: they overestimated the growth in the traffic baseline from 2002 to the time that tolling started, and they underestimated how many cars would avoid 520 after tolling began (even though they knew there were toll-free alternatives just down the road). It’s almost as if there’s a pattern here…as if, just maybe, the Puget Sound traffic models just don’t work all that well.
In fact, given the numbers to date, I think it would be fair to ask whether WSDOT really knew what it was doing when it decided that it absolutely needed to build a 6-lane bridge.
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UPDATE: How Much Do Drivers Pay for a Quicker Commute? (From Sightline.)
New evidence suggests that it’s less than we think.
So far, the High-Occupancy Toll (HOT) lanes have attracted far fewer toll-payers, and much less revenue, than the early forecasts had predicted. …
So why were those projections so over-optimistic about the HOT lanes’ appeal? It isn’t because the HOT lanes haven’t been working. In fact, according to WSDOT, the HOT lanes consistently offer a faster, more reliable commute than the regular lanes. The HOT lanes are working pretty much as advertised.Instead, we suspect that there are two reasons for the unduly rosy forecasts. First, the early projections overestimated how quickly traffic would grow over time. Second, planners may have overestimated how much drivers are actually willing to pay for a quicker trip.
What are the traffic counts for the adjacent ‘free’ routes???
There’s gotta be an interesting study in psychology here somewhere. Drivers seem relatively insensitive to the cost of gas, probably because it’s a weekly or monthly expense that’s not associated with the cost of any particular trip. But as soon as you tie the cost directly into the trip, a significant proportion of them suddenly realize that alternatives such as ride sharing or combining trips make a lot of sense.
You can campaign as much as you want, but if you really want to influence behaviour it seems that there’s no better way than to associate direct costs with it.
“The bridge carries 115,000 vehicles per day but was only designed to carry 65,000″… It’s as if the Patullo was tolled and the new Port Mann was free.
re Gas. the extra 2.7 miles vs the toll…disregarding congestion may be less than the toll. (Average gas cost to drive 2.7 miles …. 4.3 km. 0.5 litres?
Microsoft Building 18 to downtown Seattle
Via 520 13.2 miles 19 minutes.
Via I-90 15.9 miles 23 minutes
Transit 37 minutes
and the toll varies..
http://en.wikipedia.org/wiki/Governor_Albert_D._Rosellini_Bridge%E2%80%94Evergreen_Point#Toll_Schedule