This thesis evaluates four signalized roundabouts in 10th of Ramadan City and examines the applicability of the HCM signalized intersection delay procedure by comparing HCM estimates with field measurements and calibrated VISSIM outputs. Field videos were used to extract traffic and delay data, while VISSIM models were developed, calibrated, and validated using field delay measurements. The comparison showed that calibrated VISSIM closely represented field delay, with a mean delay of 52.92 s/veh compared with 50.61 s/veh in the field, while HCM produced a higher mean delay of 67.39 s/veh. Regression analysis showed stronger agreement for field–VISSIM delay (R² = 0.9937) than field–HCM delay (R² = 0.9303). Two enhancement scenarios were tested, and conversion to a conventional signalized intersection achieved greater delay reduction than signal timing optimization, especially where through movement was dominant.