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Tunnel Speed Indicator

 LED chase sequence at 55mph to prevent tunnel slowdown
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I live in Pittsburgh, PA, where 3 tunnels lead into the city, and there are many more nearby... One of the chief travel annoyances is the inevitable slowdown of people travelling through the tunnel: 70mph-->45mph-->70mph. I propose a LED arrow on the roof of the tunnel that scrolls at 55mph (or PennDOT specified other speed). If you see the arrow 'beating' you then speed up, etc. This might alleviate some of the problem. Or cause wrecks by ppl looking at the ceiling... I just don't understand the slowdown to begin with -- if I had 23K tons of dirt above me, I'd want to get the heck outta' there ASAP.
—ruxpin76, Feb 11 2004

Standing traffic waves http://www.amasci.c...raffic/trafexp.html
Related phenomena, without the tunnel, and one's guy's "experiment". [DonBirnam, Oct 04 2004]

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       How's the weather, [ruxpin]?   

       Difference in tunnel speed probably has to do with change in light more than anything else. Especially if it's sunny.
—k_sra, Feb 11 2004
   

       [k_sra] is right. However, do you want people to be driving faster than they are comfortable driving? It may be something you would have to live with, for the sake of safety.
—Baker^-1, Feb 11 2004
   

       I thought we did this idea before, though not specifically for tunnels, but I can't find it.
—krelnik, Feb 11 2004
   

       [ruxpin76] the idea is good but dont you think its something that has the possibility of causing a pile up? and because that possibility lingers its something no state agency will take the risk of implementing.
—nomadic_wonderer, Feb 11 2004
   

       Perhaps the advised speed could vary depending on traffic flow, or how heavy traffic is at that time?
—DonBirnam, Feb 11 2004
   

       [DonBirnam] that means adding a real time relay camera, calculating the average or point traffic speed and moving the arrows accordingly. Seems a bit complicated.
—nomadic_wonderer, Feb 11 2004
   

       Use a pair of sensor loops in the lanes and you can approximate average speed when the cars pass over them. Much easier than cameras and computers.
—KLRico, Feb 11 2004
   

       Alternatively, you could pay people to drive through the tunnel with their headlights on full beam six inches from the people in front. Because everyone knows that's the best way to get other drivers to increase their speed.
—kropotkin, Feb 11 2004
   
      
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