Quote:
Originally Posted by SebC
I noticed the 1st and 2nd ones still have an on-ramp and off-ramp in quick succession, although not quite a weave zone because it's a single lane segregated from the traffic going straight. Is that why they're considered "modern" designs? Couldn't you do the same thing with a full cloverleaf, no extra structures required? Would it then also be considered "modern"?
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You still can do successive cloverleaf ramps, provided that the traffic using them is quite low. In the McKnight/36th case, the amount of traffic turning from SB to EB is very low, and the traffic turning from WB to SB isn't very high either. NB to WB is a bit more, but still not too much. The EB to NB ramp has tons of traffic, that's why it got the flyover.
It the case of Deerfoot/Stoney, the two cloverleaf ramps will easily be the two least used left turn ramps, they are completely separated from the main traffic, and the hugeness of the interchange allows the weave zone to still be quite long. Shouldn't be a problem I don't think.
Also, most rights of way don't have the required amount of land to build a full cloverleaf that could actually work. Where there is enough room, the room is likely left because the designers wanted to build high speed ramps at that interchange - something cloverleaf ramps cannot be.