Previous studies have documented increased injury risks for high‐body mass index (BMI) and older drivers in frontal crashes. Laboratory studies have shown that age and particularly high BMI is associated with poorer lap belt fit. This study used three‐dimensional body scan data to examine the contour of the lower abdomen in the area in front of the pelvis. Laser scan data from 89 men and 94 women in an automotive posture were used to calculate a contour spanning the area between the anterior‐superior iliac spine landmarks. The analysis showed the contour length was strongly associated with BMI and weakly with age. High‐BMI drivers had up to 3 times greater contour length. These results suggest that even with optimal lap belt routing high‐BMI drivers will interact differently with the lap portion of the belt than lower BMI individuals.