Partial Cloverleaf Interchange - Implementation

Implementation

In California, Caltrans currently has a policy that whenever cloverleaf interchanges between freeways and surface streets are being rebuilt to handle higher traffic loads, they are turned into parclo interchanges by removing some of the loop ramps (or in rare cases bridges will be added between adjacent loop ramps — see cloverleaf interchange for details). However, as for cloverleaf interchanges between freeways, they are being unwound into partial stack interchanges or made safer with slip ramps as funds permit. Ontario has a similar policy, having upgraded many full cloverleaf interchanges to six-ramp parclos in the 1990s.

Various forms of parclo interchanges are used on the North Luzon Expressway in the Philippines. The configuration of parclo interchanges (particularly those of the "folded diamond" type) allows for the consolidation of toll barriers at points where onramps and offramps run alongside each other. A single large barrier can serve each onramp/offramp pair simultaneously, reducing construction and operation expenses.