Units were dispatched to Interstate 95 South Bound for an accident with injury possibly trapped early in the morning on November 23rd, 2005. The first due units entered onto the onramp to the interstate and realized that the accident was adjacent to the onramp but on the other side of a jersey barrier. The plan was to have the rescue engine stop traffic southbound and have the ambulance go to the end of the ramp and then proceed north in the southbound lanes. The EMS unit stopped and dropped the crew off to start patient care. The ambulance and its driver proceeded down the onramp, slowed and prepared to make a left into the southbound lanes. Suddenly, a fully loaded dumptruck tractor trailer smashed into the rear of the ambulance. The ambulance took a violent 90 degree turn to the left. It sustained serious damage and left the driver of the ambulance injured. This procedure is common practice and has proven to be beneficial for patient care considering the distance to the next exit. In addition, it has proved to be safe in the past if traffic is stopped completely. What we didn’t realize or think of in this instance was that there was an additional travel lane which allowed citizens to bypass the accident and then get back onto the southbound onramp, therefore, never leaving the interstate. The dumptruck did just that. We are now reviewing our policies to determine if we are going to continue this practice. It has cost us an injury, close call, and a totaled ambulance.