I’ve written of the freeway merging process multiple times. There are many things to consider when using freeway entrance ramps including the use of their counterparts — exit ramps. New drivers name freeway merging as among the most difficult driving tasks to master. Drivers ideally must do their best to match freeway traffic speed as they enter seamlessly into a traffic gap. Correspondingly, drivers should exit the freeway at freeway speed and slow down after they leave the highway.
But reader S. wonders: “So if you are supposed to use the ramps to accelerate, why are so many of them built with such sharp curves? You can only accelerate safely right as you begin to merge on the highway. I’m not a stunt car driver, and I’m not going to go as fast as I can trying to hold the car on the road. So ... why do they build some ramps like that when it seems to undermine the idea of ‘getting up to speed’”
I have often wondered the same thing. As aforementioned, it’s desirable to match freeway traffic speed by the time you reach it and conversely, stay at freeway speed before you leave it. That’s corroborated by Washington State Troopers I've ridden with, who always note drivers’ failures to use the entrance or exit ramp to accelerate or decelerate properly. That is of course, when it is possible to do so, which is not always the case, as S. opined.
I first broached the shortcomings of some on and off ramps in downtown Spokane years ago with Al Gilson, Washington DOT spokesman — most notably, the very short “chute” leading to I-90 eastbound from US195 northbound. Reaching speed there is no problem, since drivers are already going freeway speed, but fitting into the traffic already on I-90 with too-little room is problematic. On other ramps, such as southbound Monroe to eastbound I-90, acceleration is difficult since drivers feel like they are going to roll over if they try to go over 30 mph on its tight curve before reaching the freeway.
Basically, regardless of curves within the exits or entrances, the lack of a dedicated straight lane at the start and finish of a curved or short on or off ramp is the design flaw I see — the state and Al Gilson know that. As I should have expected, money is the answer to why all ramps are not ideal from a traffic engineering (efficient flow) standpoint. Gilson said that such ramps were adequate 50-60 years ago when built, but revising the US 195 ramp to today’s standards would cost over $170 million including moving a railroad bridge. Cost was a major consideration back when built, but prohibitive now. Spokane, as a community, was generally against I-90 construction, so gathering state funds was not likely a priority — then or now.
So, on outdated ramps (without today’s longer merging-lane requirements) drivers should be able to follow the posted speed on entrance ramp curves to avoid losing control without criticism. But then, when the curve turns straight, they should pick a spot in traffic and floor it!
If money were no object, every ramp would have dedicated, ample speed-up and slow-down lanes adjacent to their highways — but since they don’t, drivers like you and I will complain about it while stunt drivers get practice.
Readers may contact Bill Love via e-mail at firstname.lastname@example.org.