The weather may be cooling down, but there is no drop in the death count on Houston roads, continuing their reputation as the nation’s deadliest.

This weekend, two crashes each claimed two lives, along with two other wrecks that sent people to the hospital. That is not unusual for a weekend in the Houston area, though these crashes were especially severe.

OUT OF CONTROL: Houston's road are deadliest in the U.S. for major metros

The carnage started Saturday around 10:30 p.m. along Texas 249.

Zachery Palazzetti was heading south in his 2018 Acura ILX when he blew through a red light at Fallbrook, crashing into a northbound Ford Taurus trying to make a left turn, police said.

The Taurus driver, Rafie Martin, and Palazzetti were both killed.

Less than three hours later, two men were killed just down the street from the Houston office of the Texas Department of Transportation, north of Interstate 10 along Washington.

A white Lexus was speeding north on Washington around 1 a.m. where the road splits into Katy and Hempstead when the car ran into a barricade.

The driver lost control and veered down into a grassy ditch before going airborne and hitting a tree, according to authorities. Officials have not confirmed the identities of the driver and passenger, but the Harris County Institute of Forensic Sciences named Robert Miller and Sean O’Neill as victims of a traffic collision.

Less than an hour after the wreck on Washington, a woman survived a plunge off an Interstate 45 overpass.

She lost control shortly before 2 a.m., along the exit ramp to Loop 610 eastbound, near Gulfgate, investigators said.

The vehicle crashed into the concrete end of the guard rail, went over the edge and flew down onto the ramp below the overpass before rolling over.

First responders pulled out the woman, and wrecker drivers worked to free the mangled car from where it had lodged in a metal guard rail.

A NORMAL WEEK: 11 fatal wrecks, 12 deaths

Wrecker drivers and emergency responders were not done yet. A dramatic three-vehicle crash around 4 a.m. Sunday left mangled car parts scattered across the road. One person was hospitalized, according to authorities.

The driver of a blue Fiat pulled out in front of two other cars headed north on Gessner near Clay around 4 a.m.

One of the other cars smashed into the side of the Fiat, spinning it around and pushing it into a Mustang in the next lane, police said.

The Fiat driver was pinned inside and had to be extricated by paramedics. He was rushed to the hospital in stable condition.

All of the crashes remain under investigation, but indications point to speed and driver inattention as likely factors. Both are persistent problems that officials concede have helped make Houston the deadliest major metro region for roadway users.

The nine-county Houston metro region according to a Chronicle analysis of 16 years of federal data, is the deadliest major metro in the country. It is No. 2 for fatal crashes, per capita, on federal highways in the 12 largest regions of the country, based on National Highway Traffic Safety Administration data. The Houston region ranks second for fatal wrecks that involve speeding and also trails only Dallas in crashes blamed on someone slamming into stopped congestion on the freeway.

Where Houston really stands out is for fatal crashes involving drugs and alcohol, the Chronicle analysis shows. Coming soon, our analysis of Houston's drinking problem.

PROBLEM SPOTS: Want to see Houston drivers slow down?

All told, the Houston area death toll across all the categories is the equivalent of three fully-loaded 737s crashing each year at the region's airports, killing all aboard. The crashes also leave family members reeling.

While drivers play a majority role in the mayhem, there is increasing awareness by lawmakers, police and local officials that changes in laws, enforcement and engineering might save lives. Still, there are limiations.

“I am sure if you ask (Houston) Mayor Turner he would love to double the police force … but it is a question of resources,” said State Sen. Sylvia Garcia, D-Houston.

Garcia tried but failed to lower the state’s prima facie speed for cities – the default speed at which speed limits are set for local streets – from 30 mph to 25 mph, citing the lives potentially saved by slowing drivers down.

New research shows a change to 25 mph works, at least in Boston. When the city dropped speeds on local, residential streets by 5 miles per hour, the odds of a car going 35 mph or more dropped by 29.3 percent, with negligible effects on travel times, according to an Insurance Institute for Highway Safety report released in August.

"Crash statistics, road use by pedestrians and bicyclists, presence of driveways and intersections, and curvature of the road are all factors to consider when setting speed limits. Our new study shows that safety benefits can be gained when speed limits take into account all road users in an urban environment," said IIHS President David Harkey.

Garcia said in Houston it also makes sense to drop other speeds around the region, perhaps to 55 mph along many major Houston highways. Technology can also help, she said, possibly by allowing TxDOT or others to change speeds based on weather conditions or even daytime and nighttime to try and corral driver actions.

Though she probably is headed to Washington to replace Rep. Gene Green, D-Houston, Garcia said she is hopeful Texas will keep tackling its road safety issues. Lawmakers on all sides of the political spectrum are sensing something must be done.

“Bottom line, I think there will be more consensus because Texas has one of the highest fatality rates in the country,” Garcia said, noting Houston’s high fatality rates helps keep the state average high.

Still, Garcia said it is going to be a long road to safer streets in Texas, where driving is considered practically a birthright.

“People joke about it, but it is really true. In Texas, when it comes to freedom or changing anything, you have to pry that gun out of one hand and the truck keys out of the other,” Garcia said.

Dug Begley writes about transportation for the Chronicle. Follow him on Twitter at @DugBegley and Facebook at @PoppedClutchCity. Send him tips at dug.begley@chron.com