long range distance tracking sensor for rfid based toll automation

[prasannac10]

friends to charge the toll amount based on distance travelled which sensor is usefull....

 

[WimRFP]

Hello,

You should be more specific (give us more details) to enable us to give you useful feedback.

 

[prasannac10]

i mean only short range(mm or cm) distance tracking sensors are available.,but v need a range of 30 to 50 meters...can v use speed sensor later v can measure distance using time..