Z activity has decreased significantly. A given dose rate reading inside « vehicle may represent less contamin- ation per unit area due to the oontritution of gama radiation from the exterior of the vwebicle, would more On the other hand, eontamination within a vehicle probably be picked up by persoaone)l than if it were on the outside. Further, it is recognized that significently high concentrations of radio-~ active fallout may accutulate im such parts as the air filters of an automobile. again, this has to be weignted against the probability that they will be handled before the activity bas decreased to low levels plus ~~ the fact that it fe relatively 4ifficult to monitor such parts on a mass besis. The uncertainties present in estirating possiblehasards fron vehicle eontazination would not Justify fine distinctions in monitoring the various parts. A thorough cleaning, inside ant otetde, would appear to be the best solution. One of the obvious ways to «vold mech of the problem discussed in Policy IV 4s to prevent vehicles entering an area during the tine of fallout. This will not prevent the first venicles ;assing through froa pleking up activity on the tires from the nighway. ‘t {a belleved, however, this will not constitute sueb a troublesoms protler and pest experience has indicated that the activity foun¢ on the tires noticeably decreased after several cars hed pessed over the highway. Further, if vehicles are not present in the fallorwt {t will nelp reduce oontarinatior of the passengers and of the insides of the wehicles, TIEN. ye reek a. atiz