Originally Posted by
Paul Barnard
...the overwhelming majority of the time a motorist runs over a bicyclist, the driver says "I didn't see him," does it not stand to reason that with 2-3 times more surface area of visibility, riders 2-3 abreast would be more likely to get the attention of the motorist?
I'll answer in 2 parts.
1. I coined the phrase around here: "You can't be TOO seen". Bright colors, flags, flashing lights, whatever it takes. I stand by this.
2. Ever heard the term "Speed Differential"?
"The speed differential is defined as the difference between the free speed at a given location and the anticipated operating speed of a device proposed at that location..." -Link
Let me explain. Many highways, especially Interstate highways have MINIMUM speed limits. This is because there is the expectation of traveling motorists as to how fast other road users will be traveling. How do NASCAR drivers operate with inches between each other at 200+ mph and and not wreck every five seconds? "Speed Differential" is ZERO. The expectation that there won't be a cow, cyclist, or some jalopy school bus smoking along at 45mph ahead of them is 100% for sure. If we added a bunch of slow moving objects to the race course the danger would increase a hundred fold (if the drivers were not informed) albeit maybe a hundred fold more interesting. Imagine a huge yellow bus with flashing lights leaving the pit area at even 70mph right ahead of a NASCAR pack moving at 200 mph. Sure they would SEE the school bus - for a split second before running into the back of it.
For instance:
California Vehicle Code 22400 VC — the minimum speed law — prohibits drivers from slowing or stopping as to impede the normal flow of traffic. The section also disallows motorists from driving at a speed below an established minimum speed limit. -Link
^^Why? Because the higher the speed differential the more danger of a catastrophic collision. Is it because the motorists CAN'T SEE the bright yellow school bus up ahead doing 40mph in a 75 mph zone? Nope. It's because motorists have the EXPECTATION that everyone is traveling at roughly the same speed. And if traffic is all bunched up at 75 mph as it arrives at the rear of the slow bus, it's going to be a free-for-all trying to dodge each other as everyone tries to slow or change lanes - none of them professional drivers.
So to answer the second part of your question (finally) it really does not matter if the pack of riders is spread out ten abreast unless the ONE car on the highway has a clear view of them, and is AWAKE, sober, and looking at the road ahead. If there are multiple cars on the highway it is highly possible that ONLY the car up front sees the pack doing 20-30 mph in a 45 zone (where everyone is driving 55 most likely). Speed Differential is the killer. Unexpected slow moving objects (cyclists) with a large speed differential to approaching vehicles is always a recipe for disaster. By some miracle it doesn't happen every 5 seconds. There is never much margin for error and the cyclist's Lycra kit won't absorb much of the impact.