CNET reports that four U.S. senators have sent a letter to Apple's iPhone software head, Scott Forstall, asking the company to remove from the App Store applications that are designed to allow users to be alerted to checkpoints for sobriety testing.

U.S. Senators Harry Reid (D-Nev.), Charles E. Schumer (D-N.Y.), Frank Lautenberg (D-N.J.), and Tom Udall (D-N.M.) are named as senders in the letter, which is addressed to Apple's senior vice president of iPhone software, Scott Forstall. No specific applications are named, but the letter highlights apps that "contain a database of DUI [driving under the influence] checkpoints updated in real-time" as well as one that sends out real-time alerts about the existence of these checkpoints.

"With more than 10,000 Americans dying in drunk-driving crashes every year, providing access to iPhone and iPad applications that alert users to DUI checkpoints is harmful to public safety," the group wrote. "We know that your company shares our desire to end the scourge of drunk driving and we therefore would ask you to remove these applications from your store."

The same letter was also sent to Google and Research in Motion to encourage those companies to remove similar apps from their application stores. Research in Motion has already agreed to remove applications offering data on DUI checkpoint locations.

While the letter itself does not specifically reference any iOS applications, a press release from Senator Schumer names Trapster and PhantomALERT as examples of free apps offering location information on such checkpoints.

In addition to real-time information on DUI checkpoints, many of the apps in question also offer information on speed traps, red light and speed cameras, accidents, and other traffic conditions, several of which have also been considered controversial, but the senators' letter focuses specifically on the DUI checkpoint functionality.