Sunshine Technologies is well known for RFID by our customers in a number of applications, especiialy for vehicle tagging. Whether you want to tag cars or large mining trucks RFID has a place.
The decision is not always simple however - passive or active tags? Well, from our experience both can work.
For short distance take a look at the Ipico integrated RFID reader and antenna.The casing is quite rugged for outdoor applications and you have the option of using Windscreen stickers or metal industrial tags. Great for distances about 5m-10m.
For bigger trucks and longer distances look at the Wavetrend products - long distance and rugged industrial tags.