10-05-2015, 01:06 PM
If all traffic EB on Erb/Bridgeport had to turn left/use a roundabout, you would gain another efficiency. Along Erb EB, people tend to crunch very tightly in the RH lane, which goes directly into the on/off ramp we're talking about. This means that you frequently see packs of multiple vehicles without any space between them trying to merge in a short, short distance. If any of them can't merge, it starts the traffic jam.
Instead, if a turn, curve, etc, forced vehicles to become more spread out, then the highway vehicles wouldn't need to accommodate as many in a pack at once (vehicles getting into that pack thanks to the final traffic light on Erb before the highway). Imagine highway cars traveling, in order, ABCDEFGH, and a pack of cars traveling, in order, 1234. The current design sees 1234 needing to merge into a new highway stream of cars A1B2C3D4EFGH, due to short merge time and car packing thanks to traffic lights as well as the lack of any speed reduction between Erb and the on-ramp (a cloverleaf is great for spreading cars out. If you spread them out, you can get them to merge more like A1BC2DE3FG4H, and each car 1234 can move up or back between easier/harder cars ABCDEFGH to merge between. When you lack flexibility, any trouble with merging creates the start of a rapidly-expanding bottleneck.
Instead, if a turn, curve, etc, forced vehicles to become more spread out, then the highway vehicles wouldn't need to accommodate as many in a pack at once (vehicles getting into that pack thanks to the final traffic light on Erb before the highway). Imagine highway cars traveling, in order, ABCDEFGH, and a pack of cars traveling, in order, 1234. The current design sees 1234 needing to merge into a new highway stream of cars A1B2C3D4EFGH, due to short merge time and car packing thanks to traffic lights as well as the lack of any speed reduction between Erb and the on-ramp (a cloverleaf is great for spreading cars out. If you spread them out, you can get them to merge more like A1BC2DE3FG4H, and each car 1234 can move up or back between easier/harder cars ABCDEFGH to merge between. When you lack flexibility, any trouble with merging creates the start of a rapidly-expanding bottleneck.