Now that the holiday season is upon us, traffic and congestion on roadways big and small is at a peak. Trucks and tractor trailers remain a common site on interstate highways and local roads. Recent data suggests that truckers are finding it harder to obtain liability insurance to cover their fleets. Some insurance companies have left the market in response to several large personal injury truck accident settlements that have been made over the past few years.

The Department of Transportation has reported that although the number of people killed in accidents with large trucks declined 20% over the past decade, the number actually increased last year. Furthermore, there has been an increase over the past few years in the number of large verdicts where juries award tens of millions of dollars or more to families of truck accident victims.

Many people point to the 2014 truck accident involving a Wal-Mart Stores Inc. truck that injured several people, including comedian Tracy Morgan, and killed one person. In that case, which did not go before a jury, the children of the man who died received $10 million in a settlement. Wal-Mart and Tracy Morgan reached a settlement for an undisclosed amount. But large truck accident settlements became more common even before the 2014 Wal-Mart truck accident case.

Starting around 2011, large truck accident settlements and trial verdicts became more frequent. There have been at least six cases where a settlement or verdict resulted in $20 million or more. Some plaintiffs’ lawyers have begun focusing on showing juries ways that trucking companies have violated safety regulations across the particular companies’ trucking fleets.

In 2013, a jury in Texas awarded $281 million to the family of a man who was struck and killed by a trick’s drive shaft that detached and smashed through the truck’s windshield. The jury determined that the vehicle had not been maintained properly. The judgment was later reduced to $105 million, and the case was settled after that for an undisclosed amount.

In 2011, a jury in Georgia awarded $40.2 million to the widow of a man killed in 2007 after a truck driver ran a stop sign and it his pickup truck. The jury’s award was later increased to more than $55 million. The trucking company admitted to liability before the case went to trial, and the truck driver was convicted separately of homicide by vehicle. The company settled the case for $42 million in 2014.

As a result, many insurance companies have raised premiums for trucking companies from 10% to 30%. Several large trucking companies have been scrambling to find insurance coverage for their fleets after Zurich Insurance Group AG and American International Group Inc., two of the biggest insurance underwriters for the trucking business, dropped coverage of most for-hire fleets earlier in 2016. Brokers indicate that both insurance companies still cover trucks operated directly by retailers and manufacturers.

Federal law requires trucking companies to cover drivers up to $750,000 per accident. Many trucking companies self-insured up to around $1 million and then buy tiers or layers of outside insurance to cover additional exposures or costs.