Speed Trap?

I'm having a little trouble figuring this one out as it seems like topless women would increase traffic accidents if they were placed along highways holding speed limit signs but apparently it is working quite the opposite in  areas in Russia known to have higher than average rate of accidents due to speeding (over 30,000 per year). Male drivers make up the largest portion of the speeders and have slowed considerably to "read" the signs held by the women. One of the women said she was happy to do the work and felt like her work was saving lives. One of the male drivers commented that he'd like to see more of this and thought it would teach other drivers to look at the signs also.