Cloverleaf interchange

One problem is that, frequently, large trucks exceeding the area speed limit roll over.

The first cloverleaf interchange patented in the US was by Arthur Hale, a civil engineer in Maryland, on February 29, 1916.

[3][4] A modified cloverleaf, with the adjacent ramps joined into a single two-way road, was planned in 1927 for the interchange between Lake Shore Drive (US 41) and Irving Park Road (ILL 19) in Chicago, Illinois, but a diamond interchange was built instead.

[10] Before the cloverleaf was replaced in the late 2000s, it was judged eligible for inclusion in the National Register of Historic Places.

The first cloverleaf west of the Mississippi River opened on August 20, 1931, at Watson Road and Lindbergh Boulevard near St. Louis, Missouri, as part of an upgrade of U.S. 66.

The first cloverleaf in Europe opened in October 1935 at Slussen in central Stockholm, Sweden, followed in 1936 by Schkeuditzer Kreuz near Leipzig, Germany.

Most road authorities have since been implementing new interchange designs with less-curved exit ramps that do not result in weaving.

These interchanges include the diamond, parclo and single-point urban interchanges (SPUI) when connecting to an arterial road in non free-flowing traffic on the crossroad and the stack or clover and stack hybrids when connecting to another freeway or to a busy arterial in free-flowing traffic where signals are still not desired.

During 2008 and 2009, four cloverleaf interchanges along I-64/US 40 in St. Louis, Missouri, were replaced with SPUIs as part of a major highway-renovation project to upgrade the highway to Interstate standards.

Numerous cloverleaf intersections in the Lower Mainland of British Columbia, Canada, require the merging of traffic from the clover directly onto the collector/distributor lane.

The cloverleaf interchange was not implemented in great numbers in the United Kingdom, because of these performance problems.

In Ireland, partial cloverleaf set-ups exist at the interchanges of the main roads out of Dublin and the M50, allowing free-flow movements in all directions.

Most cloverleaf interchanges have been phased out in Ontario, but some close variants do remain with similar traffic flows.