approximately eight six seconds 86 s following the restoration of the lag eye signal 45 depending on the road contour and access lanes it is possible for a bouncing underheight vehicle or an overheight vehicle to pass the device 20 in the opposite direction of any overheight obstruction to reduce the possibility of false alarms under these conditions the device 20 disables itself for a short period of time to reduce the likelihood of such inputs causing erroneous overheight alarms therefore as shown in fig1 if the lag light signal 45 is interrupted before the lead light signal 42 a short lockout timer 230 generates a signal to prevent the propagation of the window pulse the duration of this lockout is about two 2 seconds a wrong way alarm could also be generated in such a manner it should be understood that the described embodiments merely illustrate principles of the invention in preferred forms many modifications additions and deletions may be made without departure from the description provided for example although the device 20 has been described as linking components via electrical connections many connections including the connections between components of the master cabinet 50 and the remote cabinet 30 could be performed by radio or other spectrum specific electromagnetic communications additionally the device 20 could easily be configured to operate from either or both north american or european standard ac power furthermore the device could be solar powered it thus is seen that a device and method for detecting vehicle overheight can be made such that anomalous data.