Studies link weed legalization, car crashes

A study found that crashes are up as much as 6% in Washington, Oregon and Colorado, compared with neighboring states that have not legalized recreational use of marijuana, CNN's Scott McLean reports.

Posted: Oct 19, 2018 10:09 AM
Updated: Oct 19, 2018 10:42 AM

The National Transportation Safety Board said Tuesday that the probable cause of a crash that killed 12 people on a church bus near Concan, Texas, in March 2017 was that the 20-year-old man whose truck hit the bus was under the influence of marijuana and a sedative.

In its report, the board says that there has been an increase in the number of drug-impaired drivers across the country and that something must be done about it.

That call to action seems to match up with a report released Thursday from the Insurance Institute for Highway Safety's Highway Loss Data Institute.

Though a 2017 study found that the legalization of recreational weed has not increased the number of accidents involving fatalities, states that have legalized recreational use are seeing more car crashes overall, according to the report, which includes two studies presented Thursday at the Combating Alcohol- and Drug-Impaired Driving summit at the insurance institute's Vehicle Research Center.

The first study found that crashes are up as much as 6% in Washington, Oregon and Colorado, compared with neighboring states that haven't legalized recreational use of weed. Researchers estimated the frequency of collision claims per insured vehicle year, controlling for differences in other factors that could contribute to an accident, including age, location, job status and weather, and still saw an increase.

The second study looked at the number of police-reported accidents before and after the legalization of recreational use of weed. The findings were similar: a 5.2% increase in crash rates after legalization than before weed was legal in those states.

Other research has found that in a small sample of drivers who used weed before driving, they had slower thinking and perceptual skills. Drivers under the influence of weed tended to weave more when tested in simulators, studies show, although scientists say more research needs to be done to better understand the correlation between blood or oral fluid concentrations and psychoactive effects of tetrahydrocannabinol or THC, the main psychoactive ingredient in cannabis.

Driving while impaired by any substance, including marijuana, is illegal in all states.

The National Transportation Safety Board said in its report on the fatal accident in Texas -- where recreational use is illegal -- that police across the country need better training and better tools to detect whether a driver is under the influence of drugs. It also encouraged the National Highway Traffic Safety Administration to come up with a system of best practices and model specifications for oral fluid drug screening devices that police can use when they pull someone over.

There are no national standards or standardized tests for weed-impaired drivers like there are for alcohol. The tests designed to determine whether someone is driving drunk are only moderately successful in determining that someone is impaired from using weed, studies have shown.

About 6 in 10 Americans support marijuana legalization, an October poll found, and thus more states will probably legalize recreational use -- meaning there will probably be more drivers on the road under the influence.

"The pick-up truck driver in this crash made terrible choices with tragic consequences," National Transportation Safety Board Chairman Robert L. Sumwalt said in a statement. "But the rising tide of drug-impaired driving did not begin with this driver, and it will not end with him. Law enforcement needs additional tools and advanced training to detect impaired drivers before they crash, regardless of the impairing drug they're using."

Mississippi Coronavirus Cases

Data is updated nightly.

Cases: 296745

Reported Deaths: 6783
CountyCasesDeaths
DeSoto19731230
Hinds18881393
Harrison16780282
Rankin12787265
Jackson12643229
Lee9703161
Madison9484203
Jones8005147
Forrest7250138
Lauderdale6847227
Lowndes6033140
Lamar590980
Lafayette5747113
Washington5229130
Bolivar4620124
Oktibbeha442194
Panola432396
Pearl River4193132
Warren4138115
Pontotoc410771
Marshall404492
Monroe3993128
Union396474
Neshoba3822170
Lincoln3564104
Hancock350277
Leflore3389119
Sunflower319286
Tate303374
Pike301796
Scott295271
Alcorn292463
Yazoo290865
Itawamba290275
Coahoma282069
Tippah279565
Copiah279259
Simpson276680
Prentiss271158
Wayne254541
Leake253172
Marion252778
Covington249780
Grenada248578
Adams235078
George232445
Newton231252
Winston221979
Jasper213845
Tishomingo212965
Attala206870
Chickasaw201453
Holmes182770
Clay179251
Stone173029
Tallahatchie171439
Clarke169672
Calhoun158528
Smith153033
Yalobusha145536
Greene127933
Walthall124540
Noxubee123131
Montgomery122939
Perry122235
Lawrence120621
Carroll119025
Amite112235
Webster111132
Jefferson Davis102731
Tunica99523
Claiborne99129
Benton93924
Humphreys93027
Kemper90423
Quitman77414
Franklin76219
Choctaw69817
Jefferson62827
Wilkinson62427
Sharkey49117
Issaquena1676
Unassigned00

Alabama Coronavirus Cases

Cases: 498076

Reported Deaths: 10094
CountyCasesDeaths
Jefferson716711387
Mobile36294737
Madison32616468
Tuscaloosa24340421
Montgomery22739519
Shelby22174218
Baldwin19873289
Lee15039157
Calhoun13832293
Morgan13753254
Etowah13390325
Marshall11448211
Houston10124264
Elmore9483190
Limestone9420138
St. Clair9022227
Cullman8984182
Lauderdale8612214
DeKalb8489175
Talladega7606165
Walker6585259
Jackson6545104
Autauga632492
Blount6236127
Colbert6001121
Coffee5264103
Dale4671107
Russell406933
Franklin399878
Covington3993106
Chilton3898103
Escambia379173
Tallapoosa3622143
Clarke344053
Chambers3431111
Dallas3422142
Pike293373
Marion288695
Lawrence284985
Winston258368
Bibb246160
Geneva240370
Marengo238857
Pickens225457
Barbour213651
Hale212269
Fayette202057
Butler201466
Henry183541
Cherokee178039
Monroe166739
Randolph164840
Washington156836
Macon147745
Crenshaw146255
Clay145954
Cleburne139841
Lamar133733
Lowndes132751
Wilcox122925
Bullock117336
Conecuh107024
Perry106127
Sumter99732
Coosa90224
Greene88532
Choctaw55323
Out of AL00
Unassigned00
Tupelo
Cloudy
51° wxIcon
Hi: 63° Lo: 42°
Feels Like: 51°
Columbus
Partly Cloudy
56° wxIcon
Hi: 67° Lo: 42°
Feels Like: 56°
Oxford
Cloudy
48° wxIcon
Hi: 59° Lo: 42°
Feels Like: 43°
Starkville
Partly Cloudy
54° wxIcon
Hi: 65° Lo: 41°
Feels Like: 54°
WTVA Radar
WTVA Temperatures
WTVA Severe Weather