Want to avoid speed traps? Well, there’s an app for that. Njection Mobile and Trapster are two apps that can help drivers avoid speed traps and costly tickets.

Whether trying to avoid school-morning traffic or the afternoon work rush, speed limit signs can be easy to overlook. Then, suddenly, the posted speed limit drops from 65 to 25 in about 10 feet.

Being a diligent driver, trying to avoid being crushed by log trucks or rear-ended by an SUV, the driver misses the speed transition.

Then the red and blue lights start flashing, the sirens are wailing, and the driver is pulled over to the curb while other drivers gawk as they fly by. Here are some of the apps that can help avoid speed situations, traffic cameras and checkpoints.

They’re updated by the users, and the user-generated updates are checked against news reports and public records.

Njection Mobile is a free speed trap app. It updates the users on speed traps, giving the type of speed trap and the distance. You can also narrow the trap search to those that are local, and it also gives you full maps and “gesture support.”

To use iHUDisplay & Speed Cams for iPhone, set the phone on the dash, and the app displays speed, direction and time on the glass of the windshield.

It appears to hover directly in front of the driver and has an alarm that goes off in the event that the car exceeds the speed limit set by the driver. It also has a speed trap alerter which can be deactivated, and it is customizable with different colors. It can be downloaded for $1.99.

Speed Cameras Maps USA is a very basic, albeit very useful, app. It contains information regarding speed cameras, check points, red light cameras and speed traps. It can be downloaded for $2.99.

Cams Ahoy! is an app that uses information for more than 3,000 camera locations to help drivers avoid speed cameras. It can be downloaded for $0.99.

Trapster is downloadable for free. Users can select to download it to their Apple, Blackberry, Android or GPS. It gathers data from over 7.2 million users worldwide, and can help in avoiding speed traps, checkpoints and more. It is available for download in the iTunes Store.