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[quote user="Falcon48"] <blockquote> <div><img src="/TRCCS/Themes/trc/images/icon-quote.gif" /> Bucyrus:</div> <div></div> But this does involve colliding with a train.  Here is some interesting information from the Nevada driver’s manual on the topic of vehicle stopping distance.  It factors in a reaction time of 2.5 seconds and gives definitions distinguishing stopping distance from braking distance.  For a typical passenger car on dry pavement, at 65 mph, it gives a total stopping distance of 494 feet.    It does not give the stopping distance for 70 mph, however it does say that if you double the speed, it increases the braking distance by a factor of four.  So, if we look at the speed of 35 mph, it gives a braking distance of 68 feet.  Then if you multiply that number by four, it gives a braking distance at 70 mph as 272 feet.   And then if you add in the 2.5-second reaction time, it gives a total stopping distance for a typical passenger car traveling 70 mph as being 527 feet.   Given the fact that trucks have a longer stopping distance than passenger cars, and given the numerical spread between the stopping distance of trucks versus passenger cars in other tables available on the web; I think that one could make a conservative estimate that the truck involved in the Nevada crash would require 600 feet to stop.   So this would confirm that the grade crossing warning for such a truck approaching the Nevada crossing northbound with its 900-foot straight approach would be 300 feet or 2.92 seconds.  What that means is that a distraction that lasts 2.92 seconds would make difference between colliding with a train and stopping time.  So you can see that there would be enough stopping distance but just barely.  A driver would have to be distracted for a collision to occur, but it would only take 2.92 seconds of distraction.  I don’t think the victims on the train would be satisfied with the explanation that they are dead because the driver was distracted for 2.92 seconds.      Here is the manual and the stopping distance is on page 31:     <a href="http://www.dmvnv.com/pdfforms/dlbook.pdf">http://www.dmvnv.com/pdfforms/dlbook.pdf</a> <div style="clear:both;"></div>   </blockquote>   This analysis is not correct because it neglects the fact (as discussed in my previous post) that the crossing signals (which, according to all reports I've seen to date, were functioning properly) would have actuated at least 20 seconds before the train entered the crossing. Therefore, the truck driver had at least 20 seconds advance warning of the approach of the train.  If he had been "distracted" for 2.92 seconds, he would still have had 17.08 seconds to stop from 70 mph.  That's over 5 times the amount of time he would have needed to safely bring his truck to a stop from 70 mph according to your figures.   <div style="clear:both;"></div> [/quote] The signals do provide a warning between the time of activation and the moment the train arrives at the crossing.  I understand that warning lasts 25 seconds.  However that warning is of no use to an approaching driver if that driver cannot see it because of a bend in the road, as there is in the northbound approach.  When a driver rounds that bend and sees the warning, he or she is 900 feet from the crossing or 8.76 seconds at the 70 mph speed limit.   <o:p></o:p> For a truck such as the one in this particular crash, requiring 600 feet to stop, that leaves a warning of 2.92 seconds, as I detailed in the post you quoted above.
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