In the mid-1980s, after EduComp moved into its big brick building at the head of Main street, Vineyard Haven, I was a frequent visitor, either renting time on the store’s laser printers or buying office supplies. One big bonus, especially in summer, was the off-street parking in the sloping dirt lot behind the building. The tricky part was — and still is — the getting in and especially the getting out. You leave the parking lot, pass alongside the building, and then start creeping across the sidewalk toward the road. To your left the road curves away, so you can’t see the vehicles rushing toward Five Corners until their fenders are a few feet from yours. When a hole appears in the traffic, likely as not there’s a pedestrian directly in front of you and gunning it into the road is not an option.

I was venting about this in the presence of company one evening when a sage and steady up-Island nurseryman observed that if everyone came down South Main at 20 miles per hour, by the time you spotted someone’s front end, you’d still have time to pull into the road and make your right or left turn. With a start I recollected that the posted speed limit around that curve was — you guessed it — 20 miles per hour.

What an epiphany! Speed limits weren’t there just to annoy me or to double-dare me to exceed them whenever conditions were fine and I thought I could get away with it. They were helping to choreograph the flow of traffic so that no one got broad-sided and no one had to wait forever. I’d be lying if I said I never exceeded another speed limit. On occasion I’ve even rolled into Vineyard Haven at closer to 30 than 20. Most of the time, though, I observe the posted limit, knowing that this will make it easier for other motorists to get out of the EduComp parking lot.

In the years since, I’ve spent uncounted hours on Vineyard roads. It’s a rare trip from West Tisbury to Oak Bluffs, Vineyard Haven to Edgartown, that I don’t get exasperated by at least one driver who’s following so close to my rear bumper that I can tell the color of their jacket. Hey, you back there! What if I had to brake suddenly? How good are your reflexes? Do you have any idea how long it takes your vehicle to stop after you hit the brakes?

When I’m bicycling or walking or riding a horse, I know for a fact that most drivers are maniacs. At a leisurely saunter or waiting to cross the road, I can see who’s phoning, who’s texting, who’s distracted by kids in the back seat, who’s fumbling with the radio, the CD player or the travel mug. On my bike I can feel cars whoosh by 18 inches from my knee. Here’s hoping the drivers’ depth perception is as precise as they seem to think.

Even if it is, pedestrians can stumble. Bicyclists can skid on sand or slip off the edge of the pavement or instinctively swerve to avoid broken glass. Horses can spook. On a windy afternoon several years ago, my mare, Allie, and I were crossing Old County Road near the Granary Gallery, about to turn right on Elias Lane. A compact wagon sped up behind us, barreling down-Island as if it was late for a very important date. A gust blew the gallery’s roadside American flag flapping in our direction. The car didn’t slow down. It didn’t pass wide. Metal hurtled past a scant two feet from Allie’s legs. If Allie had spooked at the flag, horse and car would have collided. I blew off the adrenaline rush by screaming curses at the long-gone vehicle.

Once I get back behind the wheel, however, the vulnerability of everyone outside my metal carapace tends to fade from my awareness unless I remember to drive with the mind of a pedestrian and cyclist as well as the straight-ahead mind of a motorist.

No island is an island, and no drivers are either. No matter how ruggedly individualist we claim to be, we are affected by the actions, inactions and inattentions of others. Our actions, inactions, and inattentions affect others, and depending on the timing, the effects can range from annoying to disastrous. Imagine a world in which most of us managed to keep that in mind most of the time — and not just on the road.

Susanna J. Sturgis is the author of The Mud of the Place, a novel. She lives in West Tisbury.