Since NASCAR originated in 1947, many helmets at the beginning were old army and airforce helmets. Originally NASCAR helmets were put in place to protect the drivers from dirt, but the overall protection of these helmets was insufficient. In the 1950 many drivers made the switch over to motorcycle-style helmets, and by the 60's motorcycle-style helmets became the norm.
Over the years, NASCAR helmets made similar safety improvements to Formula 1. NASCAR helmets now include the use of the HANS device as well as the layers of foam in the helmet to protect the driver's head.
The main difference between NASCAR helmets and F1 helmets was how long it took NASCAR to require the full-face visor. It was a controversial addition at first since the main concern was that it would affect the driver's visibility while racing. Eventually in 2001 due to the death of Dale Earnhardt, full-face visors were required in the sport.
These helmet photos were taken at the New England Racing Museum, in Loudon New Hampshire.
This helmet work by Reino Tulomen is a perfect example of what helmets used to be before safety improvements were added. Tulomen's helmet resembles that of a WWII soldier's helmet and shows its history through all the dents it has during racing. While this helmet looks cool, it's missing some key factors such as a lack of face covering, any sort of fire resistance, and the absence of the HANS device.
This helmet was worn in 2003 by Ricky Craven. This helmet was in use 2 years after major changes in helmet safety. In 2001 NASCAR made full-face helmets required, as well as making the HANS device necessary. In this photo of Craven's helmet, you can see the silver bolt that the HANS device would attach to.
From New England Racing Museum
to keep drivers safe, and strapped in NASCAR uses a 5-point harness. This restraint system somewhat resembles a seatbelt except that it goes over both shoulders. These harnesses are key safety features when it comes to a collision. The harness helps transfer the driver's energy in case of a crash and even stretches a little, which limits the force on the driver.
The five-point harness comes down on each shoulder, twice around the waist, and one more strap between the legs. As seen in the photo, the harness has padding on the shoulders. This padding is made from nylon. This type of seatbelt is much stronger than a seatbelt in an average car.
Generation 2 of NASCAR, spanning from 1967-198- came with a handful of safety improvements, the most important one being the Roll Cage. Because of the addition of the roll cage, generation 2 and Beyond of NASCAR no longer had opening doors, and drivers had to enter the vehicle through the window opening.
As seen in the photo, the roll cage goes around the entire frame of the car. The main purpose of this is to keep the car together and prevent it from collapsing in on itself, in the event of a crash. By keeping the car together it minimizes the risk of injury to the driver.
From NASCAR Hall of Fame