Many active safety systems are being developed with the intent of protecting pedestrians namely; pedestrian airbags, active hood, active emergency braking (AEB), etc. Effectiveness of such protection system relies on the efficiency of the sensing systems. The pop-uphood system was developed to help reduce pedestrian head injuries. A pop-up system is expected to make full deployment of the hood before the pedestrian’s head could hit the hood. The system should have the capability to detect most road users ranging from a six year old (6YO) child to a large male. To test the sensing system, an impactor model (PDI-2) was developed. Sensor response varies for vehicles with different front end profile dimensions. To study numerically the sensor response characteristics with respect to different front end parameters, (a) PDI-2 FE model was developed and validated, (b) FE model of sensor was developed and validated, (c) Sensor FE model was incorporated in the vehicle and it was simulated against the PDI-2 FE. The results were validated with physical experiments, (d) Vehicles with different front end profile models were developed and finally (e) Sensor response were studied using different vehicle designs simulated against PDI-2 FE and 6YO-child FE model. Results shows that for PDI-2 impacts, bumper height, bumper upper lead and bumper lower lead have influence in pressure sensor response. For 6YO-child impacts, the bumper height has influence in pressure sensor response.