If you see a sign that reads “90-degree rule in effect today,” or something similar, the meaning is really not as ominous as it may seem. All this sign, or the helpful attendant at the pro shop, means is please keep your golf cart on the path, except for a right angle turn across the fairway directly toward your ball and back. This also includes driving between each member of your group’s ball as it lies. Rather than drive directly between balls, it’s asked that you drive straight back to the path and repeat the process each time.
The details
The use of the word “rule” is actually a bit misleading. The 90-degree rule is not one of the “official rules” published by the USGA. It is, however, part of official etiquette guidelines that you are expected to know in order to respect the course’s protocol.
Sometimes courses will put the 90-degree rule in effect in an effort to maintain the structure and quality of their grass. Mostly, courses will instate this rule if their grass is in a particularly delicate stage of growth, or recent rains have made the fairway particularly muddy or swampy and they want to prevent damage or erosion. During conditions like this, some courses will forbid any golf carts on the fairway at all. This is called the “cart path only rule,” which is a bit sterner. And some courses that have unpaved paths will only allow you to walk the course carrying your bag or with a caddy during a delicate period.
A few select courses have the 90-degree rule continually in effect. What is the reasoning behind forbidding carts on the fairway ever? If you are very serious about your game, you might be in this camp. Besides the risk of damaging turf, even on a very dry day, golf carts always flatten grass blades. That’s just the reality. If a course wants to provide each golfer with a nice clean lie on beautiful, fluffy grass, then following the 90-degree rule (or even the cart path only rule) starts to make sense.
The reasoning
You have high expectations for the golf courses you play at. You expect ponds dotted with water lilies, a few sculpted hazards full of pristine white sand, and greens that look like they were trimmed perfectly with nail scissors. Especially if you’re playing at a private club, you expect conditions to always be beautiful. But have you ever really considered just how much work goes into maintaining all that incredible landscaping, especially with dozens of golf carts roving the fairways each day?
Spoiler alert — it’s really hard to maintain the perfect course environment. From watering and trimming the grass to several different lengths with perfect precision, to filling in daily divots, to keeping flying geese out of the ponds and your line of flight, golf course landscaping is a painstaking and expensive process. Under some conditions, it makes very good sense to ask players to minimize their potential damage to that picturesque fairway you’ve come to expect.
The takeaway
Most golf courses do allow carts to drive freely across the fairway, as long as you stay far away from the greens (a good rule of thumb is at least 20 feet away). At your average course, you can assume the fairways are fair game, unless there is a notice posted or it’s verbally given. If you are at a particularly nice course, you’re somebody’s guest or you simply want to play it safe, it’s always respectful to just go ahead and follow the 90-degree rule on your own. But if you’re ever in doubt, it never hurts to ask at the pro shop.
— Cammy Pedroja