Signals on freeways

2oldman wrote:
I received a response today:

From a 1987 memo:
Studies indicate that the use of active narrative signs that say "Prepare to Stop", or variations of this message, are generally not effective warning devices for motorists approaching a signalized intersection. Accident statistics do not indicate any reduction in accidents when these "Prepare to Stop" signs are installed or, conversely, any increase in accidents when such signs are removed.

Therefore:
* No new installations of active "Prepare to Stop" signs, or variations of this message, should be made; and
* Existing installations should be reviewed to see if other treatment is more appropriate."
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I also received this attachment from:

Antonio Sarmiento, P.E.
Office Chief, D08 Electrical Operations Riverside
California State Department of Transportation
464 W. 4th Street, 6th Flr MS-713
San Bernardino, CA 92401-1400
(909) 383-6427
mailto:tony.sarmiento@dot.ca.gov


No. It has been determined that the "Prepare to Stop" message is not an effective warning sign, thus the Department is not installing that or any variation of such message on an approach to a signalized location on a State highway.
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My response:

Thank you for responding.

How do you gather data on ".. are generally not effective warning devices"? What does 'effective' mean? They may not be effective for automobiles, but for heavy trucks and people like me towing large trailers, they are. They provide just that much more time to slow down, rather than trying to guess what's going to happen. Accident statistics are what they are, but, as I mentioned in an earlier reply, the skid marks on the 86 may provide ample evidence of panic stopping. I can't imagine an OTR trucker saying "No, we don't need warning lights to tell us when to begin slowing down, we'd rather guess."

Canada has been employing these warning signs for decades, according to folks I talk to. I don't know what studies they go by, if any. Perhaps they just feel it's a nice thing to do for the heavy trucks. After all, if the statistics say it can't hurt, then why not?

gee, when I approach an intersection and the light is blinking warning me of an impending red light, I slow and stop. if the light is not blinking, I maintain my speed and hit the intersection on a green light. did those "1987" studies say which direction/entry to the intersection was used by the car causing the wrecK? and blind following on "statistics" without using reason is dangerous.
bumpy