NCJ Number
63355
Date Published
1975
Length
29 pages
Annotation
THE USE OF THE TRAFFIC TEMPLATE IN DEVELOPING MEASUREMENTS AND DIAGRAMS IN ACCIDENT INVESTIGATION AND PROCEDURES FOR CONDUCTING SKID TESTS ARE DISCUSSED IN THIS MARYLAND POLICE TRAINING UNIT.
Abstract
MEASUREMENTS AT THE ACCIDENT ARE SAID TO MAKE IT POSSIBLE TO LOCATE SIGNIFICANT OBJECTS AND EVENTS AT THE ACCIDENT SCENE AND REDUCE APPROXIMATIONS IN ACCIDENT RECONSTRUCTION. THE GENERAL MEASUREMENT PROCEDURES DISCUSSED ARE THE DECISION AS TO WHICH ITEMS NEED IMMEDIATE MEASUREMENT, THE DETERMINATION OF HOW THE MEASUREMENTS WILL BE RECORDED, AND THE TAKING OF THE MEASUREMENTS. TYPES OF MEASUREMENTS CONSIDERED ARE LOCATION MEASUREMENTS AND SKIDMARK MEASUREMENTS. PROCEDURES FOR CONSTRUCTING A FIELD SKETCH AND A SCALE DIAGRAM ARE ALSO DESCRIBED. IT IS NOTED THAT TO MAKE ACCURATE ESTIMATES OF MINIMUM VEHICLE SPEED FROM SKIDMARKS. IT IS NECESSARY TO DETERMINE THE SLIPPERINESS OF THE PAVEMENT. A SKID TEST IS INDICATED TO BE THE BEST MEANS FOR DETERMINING THE DRAG FACTOR. IT IS ADVISED THAT, IF POSSIBLE, THE ACCIDENT VEHICLE SHOULD BE USED TO MAKE THE SKID TEST, OR A VEHICLE OF SIMILAR WEIGHT AND TIRE CONDITION. THE STEPS INDICATED ARE (1) SELECT A SAFE AREA FOR THE TEST AS NEAR THE ACCIDENT SCENE AS POSSIBLE, (2) SELECT THE SPEED FOR THE TEST SKID (GENERALLY A SPEED OF 35 MPH OR THE SPEED LIMIT, IF LESS, IS SATISFACTORY), (3) CONDUCT THE TEST WITH VEHICLE SPEED ABOUT 3 MILES PER HOUR FASTER THAN THE DESIRED TEST SKID SPEED AND THEN DROP TO THE DESIRED SPEED BEFORE APPLYING THE BRAKES SUDDENLY AND FIRMLY UNTIL THE VEHICLE COMES TO A COMPLETE STOP, AND (4) MEASURE AND RECORD THE LENGTH OF THE TEST SKIDMARKS. THE PROCEDURES FOR DETERMINING THE DRAG FACTOR FROM THE SPEED MONOGRAPH IS DESCRIBED. A TEST COVERING THE MATERIAL PRESENTED IS INCLUDED. (RCB)