Allstate's Drive Wise

Allstate has been expanding the product and is now available in 49 states. The plug-in stats are used to decide if you get a 10% discount for the first policy term. Allstate says good drivers who rack up a few miles during following terms may qualify for up to a 40% discount.

American Family Insurance's DriveMyWay

American Family says customers can receive a 10% "introductory" discount by installing the DriveMyWay. If you renew after six months, the discount can be between 5% to 20%. Not available in every state.

Esurance's DriveSense

The plug-in transmits details through Sprint's wireless network to Esurance, determining if drivers qualify for discounts up to 30%. Esurance has expanded the availability of DriveSense in the past year; it's now available in 35 states, including Alabama, Arizona, Idaho, Iowa, Illinois, Michigan, Nebraska, Rhode Island, South Dakota, and Texas.

National General Insurance’s DynamicDrive

Once you enroll in National General Insurance’s DynamicDrive program, you will instantly receive a 10% discount on your auto insurance. The Routely app provides valuable insights into your driving patterns; this data can earn you a discount on your car insurance.

The Hartford's TrueLane

A plug-in transmits details to the insurer through its partner, Octo USA Inc., over that firm's cellular network. This is another one that gives a 12% discount for just signing up. The Hartford says that you can earn a discount of up to 25% on renewal based on the safe driving habits you exhibit.  TrueLane is offered in Alabama, Arizona, Arkansas, Colorado, Connecticut, Idaho, Illinois, Iowa, Maryland, Minnesota, Missouri, Nevada, New Mexico, New York, Oregon, Oklahoma, South Carolina, Vermont, Virginia, West Virginia and Wisconsin.

Progressive's Snapshot

You can avail the usage-based discounts from Snapshot by enrolling on the plug-in device or mobile app. Progressive aggressively markets Snapshot and offers it in most states, except California.

Recently Progressive announced that some drivers may see rate increases at renewal time rather than discounts, but that proviso affects only new customers.

Safeco's Rewind

The company, which is owned by Liberty Mutual, offers a PAYD for motorists who are paying higher insurance rates because of traffic tickets or accidents. A device monitors their driving and, after four months, the record is evaluated by Safeco, which may reduce or eliminate the premium increases that came because of the prior accidents or violations. Rewind isn't available in every state.

State Farm's Drive Safe & Save and In-Drive

If you sign up for Drive Safe & Save, you can receive a discount on your car insurance of up to 30%, depending on how you drive. You even get a discount of 10% just for signing up. Drive Safe & Save offers different product options with various safety and security features to choose from. The insurer also offers In-Drive, which like most other pay-as-you-drive plans, uses an OBDII plug-in to track your mileage and driving habits.

The programs are available in all states except California, Massachusetts and Rhode Island.

Travelers' IntelliDrive

Travelers IntelliDrive can cut premiums by as much as 30%, according to Travelers. Available in Alabama, Connecticut, Indiana, Illinois, Maine, Ohio, Oregon and Virginia.