Cloverleaf Interchange

Photo Credit: Brian Wolfe

This is a great example of a classic cloverleaf interchange of a major road and a highway. The cloverleaf interchange gets its name from its shape. Half of the ramps, where the driver would normally make a right turn at an at-grade intersection, are smooth curves on the outer edges of this interchange. The other half of the ramps, where the driver would normally make a left turn to get on the other road, are 270-deg loops on the inner part of the interchange. They have been a popular choice by transportation engineers for many decades, but recently they are being replaced by safer and more efficient interchanges. The problem with the cloverleaf interchange has to do with the merging in/out of the loop ramps, especially when there is a heavy slow-to-accelerate truck in the mix which are also prone to roll-over accidents.