An analysis of public posting in reducing speeding behavior on an urban highway.

Houten et al. (1980) put a big sign beside a busy city highway. The sign showed yesterday’s percent of drivers who stayed under the speed limit.

They flipped the sign on and off four times. This ABAB design let them see if the sign itself changed driver speed.

When the sign was up, fewer people sped. When it came down, speeding crept back up.

Updating the number once a week worked just as well as updating it every day. The effect lasted at least six months.

Davison et al. (1989) tried the same sign idea nine years later. They found no drop in speeding at all. The roads looked the same, but the drivers or the traffic culture had changed.

Greene et al. (1978) used the same ABAB reversal logic to test police helicopter patrols. Their crime curves moved just like the speeding curves in V et al., showing the design works outside clinic walls.

Lowe et al. (1977) and Malagodi et al. (1975) also tracked city-level safety programs with time-series methods. Together these papers show behavior analysis can measure real-world interventions, but each setting needs its own test.

You now know that public feedback signs can cut speeding, but the effect may fade in new decades or new towns. If you partner with city planners, start with a short ABAB pilot. Post the sign, remove it, and watch the data. One weekly update is enough, so staff time stays low. If speeds don’t budge, follow M et al. and try a different cue or added consequence instead of blaming the drivers.