About 439 people will die and another 50,500 will suffer serious injuries in vehicle crashes during the Memorial Day holiday weekend, according to the National Safety Council.

If the estimate holds, this will be the deadliest Memorial Day holiday since 2009, when 462 Americans were killed on the nation’s roadways, according to federal data.

The estimate comes as traffic fatalities continue to trend upward. In February, the council released preliminary estimates showing motor vehicle fatalities had increased 8% in 2015 compared to 2014 — the largest year-over-year percentage increase in 50 years. Memorial Day also marks the unofficial start of summer, which is always a dangerous time on the roads. More than 9,570 people died on U.S. roads in 2014 from May 24 and Aug. 31.

“As Americans gear up for the most carefree months of the year, we cannot take our safety for granted,” said Deborah A.P. Hersman, the council's president and CEO. “Driving is one of the riskiest things we do every day. Engaging our defensive driving skills and staying alert can mean the difference between attending cookouts and family parties or spending the evening at the emergency room or worse.”

The council attributes the spike in fatal car crashes partly to an improving economy with lower gas prices and lower unemployment rates. Certain crash factors, such as speeding and alcohol, are also more common during the summer.

To help stay safe on the roads this summer, the council recommends:

• Make sure passengers buckle up for every trip. The council estimates 104 people could be saved this Memorial Day holiday if they buckle up.

• Designate an alcohol- and drug-free driver or arranging alternate transportation

• Get plenty of sleep and take regular breaks to avoid fatigue on long trips

• Never use a cell phone behind the wheel even hands-free.

• Stay engaged with your teens’ driving habits. An NSC survey found many parents are more inclined to loosen household driving rules during the summer.

• Learn about vehicle safety systems and how to use them. NSC’s online tool MyCarDoesWhat? can help drivers understand the ins and outs of features such as adaptive cruise control, automatic emergency braking, blind spot warning systems, and backup cameras.