New cellphone driving laws go into effect Wednesday in Idaho, Indiana and South Dakota. How effective are similar bans in other states?

Three more states will prohibit the use of hand-held cellphones while driving, beginning Wednesday.

Idaho, Indiana and South Dakota will join 22 other states that already require phones be in hands-free mode, according to the Stateline, an initiative of The Pew Charitable Trusts, amid ongoing efforts to reduce distracted driving fatalities across the nation.

The Idaho State Police told the Idaho Statesman that law enforcement will issue warnings until Dec. 31 and work to educate drivers about the new law. Citations will be issued as of Jan. 1, 2021.

In Indiana, the new statute says that a driver can be stopped by police, fined up to $500, and potentially lose their license for having a phone in their hand while driving – regardless of the phone is being used.

South Dakota residents will be prohibited from using a cellphone except for emergency purposes, using a GPS app, or reading or entering a phone number.

Virginia has also passed a law to bar the use of handheld phones while driving, effective Jan. 1, 2021. Other states, including Michigan, Ohio, Pennsylvania, and South Carolina, also have bills in their legislatures.

Distracted driving resulted in 2,841 fatalities in 2018, according to the National Highway Traffic Safety Commission. Forty-eight states and the District of Columbia have banned texting while driving — only Montana and Missouri don't have such a law for all drivers — according to the National Conference of State Legislatures.

"The goal was not to create a law where you can write a bunch of tickets and come across with a heavy hand of enforcement. It was about trying to change behaviors and hopefully save some lives and injuries as well," South Dakota Rep. Doug Barthel told The Argus Leader of Sioux Falls, part of the USA TODAY Network.

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How effective are such bans? Studies have produced mixed results.

A 2011 study looked at data before and after handheld phone bans in California, Connecticut, New York and the District of Columbia, but found no evidence of a decrease in crash risk.

Another study, published in 2013, found that cellphone bans reduced fatal crash rates for drivers between ages 18 and 34, but not drivers older than 55.

Predominant research, however, indicates that cellphone bans while driving do help reduce crashes.

The 2008 hand-held cellphone ban in California reduced 66.4% of cellphone usage-caused crashes, reported a 2019 study.

A 2012 study found a similar correlation in New York: the hand-held cellphone ban, implemented in 2001, reduced deaths by 7%.

Another 2019 study found that prohibiting dialing, texting or emailing while driving reduced total daily traffic fatalities by 26% in the U.S.

Co-author Nicholas Wright, assistant professor of economics at Florida Gulf Coast University, said cellphone use increases both the likelihood of an accident because "inattentive drivers are less aware of their surroundings and are slower to react to unexpected roadway conditions."

"Estimates from the National Highway Traffic Safety Administration suggests that this phenomenon imposes a cost of about $123 billion on the U.S. society and accounts for approximately 15% of the total societal harm caused by motor vehicle crashes," Wright told USA TODAY. "Consequently, this is a significant public health concern that requires immediate attention and direct policy intervention."

This article originally appeared on USA TODAY: Cellphone driving laws start Wednesday in Idaho, Indiana, South Dakota