Part of current street layout dogma is that at every place where streets cross, there must be an intersection. Suppose the major streets are in a nice grid layout. Convert every 3rd intersection to an overpass and ditch those traffic lights. There would NOT be an interchange. It's a worthwhile tradeoff: a little inconvenient for things near the former intersection, vs. 1/3 less traffic lights.
Biggest problem is money for the bridges. I mean, if people aren't willing to cough up money to eliminate all intersections of roads with railroads, where no one ever has a reason to turn (except possibly those special trucks equipped with wheels for rails, and they've got designated access points for that) then this'll never happen.-- ThotMouser, Apr 18 2002 "fewer"-- mcscotland, Apr 18 2002 Remember: "Fewer is more." (famous architect).-- bristolz, Apr 18 2002 For a fraction of the cost of a full bridge, you could just build a ramp in one lane of every intersection and let cars jump over.-- spartanica, Apr 18 2002 How about a phase displacement mechanism, whereby a fluctuation in the space-time continuum at each crossing (only for one road to keep costs down) causes cars to phase shift on their way across the intersection, so that they just pass right through the cross-traffic. I don't know if this would be cheaper, because I don't know how much it costs to install a phase displacement mechanism large and powerful enough to instantly phase shift several lanes of vehicles, but it would virtually eliminate accidents.-- globaltourniquet, Apr 18 2002 globaltourniquet, that's really technologically sweet. If, of course, we could do it.-- Dog Ed, Apr 19 2002 405 North 1 Mile 405 South 1.5 Miles 101 South 5 Miles Wormhole 7 Miles-- thumbwax, Apr 19 2002 How about a lightning-fast turntable with one roadway as used to switch train engines. The vehicles' speeds would have to be phased in so that the turntable could be entered at near-normal speed. Left and right turns/U-turns would be achieved when the turntable turns 90/180 degrees.-- FarmerJohn, Apr 19 2002 Now I know what was bugging me about the title. Don't suppose I can edit? Meanwhile, I refer you nitpickers to Pedants Anonymous. http://www.halfbakery.com/idea/Pedants_20Anonymous#1020132845
[spartanica] I've already thought about jumps. It could be done. A traffic lane is 12 feet wide. At 60 mph (88 feet per second), a car will travel that distance in 0.136 seconds. From rest, an object will fall 16 feet in the 1st second. Figure on a less than 2 foot drop to get over a lane. Add in a bit of a ramp and beef up the suspension a bit, and a jump should be no problem.-- ThotMouser, Apr 30 2002 You can edit the title (or anything else you have written at the HB) by following the [edit] link which appears under the text that you wrote.-- BigBrother, Apr 30 2002 random, halfbakery