While I did my search for my SPLmeter, I found out most cheap type of meters (in Europe, RadioShack SPLmeter-alikes) are "Class 2", ranging from 50-126dB max. "Class 1" meters are for law enforcement and they range from 30-140dB. The last type starts from 300-400€ and up.
I haven't found any meter capable over 140dB, let allone an affordable one.
Try to get an RS-alike, and take more distance till you are in range. Then add +6dB for every 1/2 distance from your car.