The Freeway and exit ramp that crosses back over the freeway, are 60 mph and suddenly at the end of the ramp is 35 mph sign without advance notice of speed reduction. Cop sits right across from sign and writes ticket location as 1/4 mile past the sign when the radar reading is for on the ramp before the 35 mph sign. The section of Rte 21 is 4 lanes, undivided, elevated, steep drop off on each side, a long bridge, more elevated with steep drop off, another bridge with cloverleaf interchange, then after 1/2 mile, a motel. Cop writes ticket as business and homes in area.