I read Mr. Jennisen's article, "ATVs' design make them unsafe on roads" (In Focus, April 27), and have it in front of me as I write this letter. I've been riding dirt bikes, street bikes, three-wheelers, four- wheelers, and finally a UTV (utility terrain vehicle, or side-by-side), for about 50 years. I have a few comments to offer.
I had considered writing a letter to our state representatives touching on a few of the same points brought up by Mr. Jennisen before his article appeared. Primarily, I was concerned about the lumping of all ATVs into a single category, when, in fact, there is considerable technological variation between the different models. An important point I considered was vehicles with open differentials (like cars), and those with solid rear axles or closed (locked) "pumpkin" gear boxes.
Most of the smaller ATVs with 250 - 350 cc engine displacements have locked rear axles. These vehicles often have either a final drive sprocket driven by a chain or a shaft drive going to a differential-like gear "pumpkin" on the rear axle. These particular ATVs are inherently unsafe on paved roads! What I mean by inherently unsafe is their locked-axle design makes turning them very difficult on paved surfaces, as there is no allowance for differential rotation of inside versus outside tire rotations when turning.
This differential rotation is critical, as the reactive forces make any sharp turns very dangerous when on paved roads. An ATV with a locked rear axle, making a sharp turn on a paved road, too often will result in a very fast rollover, with the rider being literally tossed off the ATV. Safety isn't the only consideration -- though it's the most important. The drive-train stresses generated under those conditions rapidly destroy tires and reduce vehicle drive-train lifespan.
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However, Mr. Jennisen was incorrect when implying that the deep-treaded ATV tires are more dangerous on the street. Those tires are designed to dig into dirt or other loose surfaces, have a smaller surface contact area, and thus have less traction on hard surfaces. A tire designed for paved roads on an ATV with a locked axle is even more dangerous than one with off-road "knobby" tires, due to increased traction on paved surfaces.
Many of the larger displacement ATVs (450-1,000 cc) are often four-wheel drive, and have three modes of final drive. They typically have a rear driven with a carlike open differential, a four-wheel drive mode, and a four-wheel drive mode with locked axles. When in the standard two-wheel drive mode, these vehicles are probably safer than any two-wheeled motorcycles, and certainly more stable. Some of the larger displacement ATVs can do 75 mph.
UTVs, or side-by-sides, should not even be lumped into the ATV category at all! I presently have a 2006 Yamaha Rhino and plan to make it street legal. Vehicles such as these typically have 13/4 inch steel cages, safety harnesses, and weigh more than 1,200 lbs. My Rhino has a governed speed of about 45 mph. Many of the newer and more powerful models have 1,000 cc engines, and can do 75 mph. These vehicles are inherently far safer than all the legal two-wheeled motorcycles (of which I've had a few).
From the standpoint of ATV injuries and death, the following is likely accurate, based on observation and literature for ATVs: Accidents typically involve, (1) Riding without any protective equipment, such as helmets, gloves, or glasses; (2) riding double on ATVs designed for single passenger use; (3) driving after consuming alcohol or other mind-altering drugs. I suggest the following recommendations for our representatives (I'm only addressing the issues outside of standard vehicle safety, like helmets, lighting, horn, etc.):
(1) ATV owner must identify if the ATV has a solid or closed rear-axle design. If the owner cannot identify this via the required dealer inspection, then the ATV should not be licensed for use on public roads. If the ATV has a closed (solid, or drive shaft with solid final drive) rear-axle design -- a red license plate sticker for public, loose surface roads only.
(2) If the ATV has an open-differential design, as determined by dealer inspection, then the ATV would qualify for licensed use on loose surface and paved public roads -- a green license plate sticker.
(3) If the vehicle is a UTV, or in the side-by-side class, the vehicle will need to meet safety inspection criteria, but should be able to travel on loose and paved surface county roads with 45 mph speed limits -- a green license plate sticker.
Representatives making laws involving mechanical technology need to create laws which reflect the (sometimes) significant design differences of these vehicles and not simply lump them all into a simplistic, single category.
UTVs should be classified like small cars or jeep-like vehicles and should not have the same restrictions as the general ATV category, beyond the same safety requirements for cars and motorcycles. The 35 mph road limit for these type of vehicles is a bit silly, and should be rationally set at 45 mph. Many manufacturers even produce these vehicles to seat four people.
-- LOU BOLIOU, Pasco