Intersection Capacity Utilization - ICU Versus HCM

ICU Versus HCM

HCM method is seen today as the more popular alternative when it comes to capacity analysis. The HCM is based on the estimated delay for an intersection. While the ICU design is compatible with the HCM design, the volume adjusted for ICU are the same as required by the HCM design. If an intersection design satisfies the HCM design, then it most definitely satisfies the Level of Service (LOS) required by the ICU.

The LOS calculated for the ICU method is often confused with the LOS calculated for the HCM method. While both LOS provide information about the performance of the intersection, the specific way in which each of these methods grade an intersection is different. The HCM LOS is delay based while the ICU LOS reports the amount of reserve capacity or capacity deficit.

Some signal timing software like Synchro report ICU Level of Service. The Level of Service is reported on a scale ranging from A to H, A being the least congested condition and H being the worst condition.