The US National Highway Traffic Safety Administration (NHTSA) announced that deadly traffic accidents in the US increased 8.1% over the first six months of this year.

The road regulator suggested smartphones and other driving distraction to be the largest cause of traffic fatalities.

NHTSA administrator Mark Rosekind told Reuters that the increase in smartphone use has the significant role on traffic fatalities.

However, the agency doesn't have enough information yet to determine how big its role is.

Rosekind suspected that smartphone activity such as texting was part of the cause of deadly traffic incidents, as well as drunken, drugged and drowsy driving, and increased driving by teenagers.

According to Oregon Live, NHTSA's research had showed that human decisions cause 94% of all traffic accidents.

Last year, the rate of traffic fatalities fell to its lowest point since Fatal Analysis Reporting System began in 1975, showing  fatality rate of 1.07 deaths per million travels or decline of 0.1%.

The statistics of traffic fatalities in 2014 showed that distracted driving caused about 10% of the 32,675 traffic deaths. But since the driver distraction is difficult to track, the numbers couldn't represent exactly the causes of crashes.

Meanwhile, in Detroit Free Press, Rosekind said that it's normal for the number of deadly accidents to increase as the economy recovers, gas prices decline, and American drive more miles.

The accident rate has increased faster than expected for the miles traveled. Americans drove 1.54 trillion miles in the first half of 2015, up 3.5% from the same period last year. The number still represents lower than 8.1% of deadly traffic accidents increase.

Rosekind stated that the governments should be adopting stricter laws to regulate the use of smartphones, sea belts, and motorcycle helmets. Such regulations could save more lives.

Some traffic regulations need improvements, for example, the US only have 24 states that use cameras to catch drivers running red lights.

Meanwhile, 16 states still do not have enforcement seat belt laws for front seat occupants and 34 states lack seat belt laws for rear seat occupants. NHTSA also mentioned that only 19 states have mandatory motorcycle helmets for all riders.

The US officials plan to hold five meetings around the country early next year to find the solutions on how to decrease the traffic deaths. Larger meeting in Washington will follow next year to present the results and submit recommendations to address the human factor.

NHTSA plans to launch a program next year to decrease traffic accidents caused by human factors. The program worthed $500 million will be funded by federal safety grants.