For several years as I travel to Bangkok from Ubon on highway 24 I have learned to slowdown when approaching "Prasat!" There is always a speed trap there where everyone is paying. After coming back here to Thailand after six months in the USA this year, traveling via 24 yesterday, I slowed down 90 K's prior to Prasat. I usually speed up to around 110 (About 70 MPH in the USA) in very rural areas on the highway and of course slow down as I enter any city on the way. However, this time as I approached Prasat at 12 kilometers prior my Uniden R3 Extreme Long-Range Laser/Radar Detector made an extreme alarm after making a turn, luckily I was at the right speed as I went thru the check point. What is new on the other side of Prasat about 12 or so kilometers after the Prasat Police had setup another check point and were grabbing more speeder thinking they were free to speedup since they had just past the last one. Food for thought-Please pay attention when getting close to "Prasat" when driving on highway 24.  "Happy Travels" 

Mrs. Shrdlu and I make a similar pilgrimage on 24 several times a year and have also seen the checkpoints near Prasat and once in a while in other places. I keep the speed under 100 kph anyway and have not been ticketed.

 

Mrs. Shrdlu after a solo trip once received a letter in the mail with a photo of our vehicle exceeding the limit. I think the fine was 500 baht. She wasn't stopped by the police at the time, so no checkpoint doesn't mean no citation! 

If you go further on the 24 down to Korat, near Nong Khi is also a hot spot for those check points. 

I use the free version of Radarbot. Can download from Google Play. There's a free and a paid version. Seems to work well in Thailand as it shows me quite a few speed and red light checks along the road.