The S21 Desert Expressway: Urumqi to Altay in One Straight Shot

The straight road that changed the north

Before 2021, reaching the Altay lakes from Urumqi meant a long loop through Karamay and Beitun, eight or nine hours of mixed highway and desert road. Then the S21 opened, a 360 km expressway that cuts straight across the Gurbantunggut Desert to Altay, and the same trip became about four and a half hours. I drove it the first summer it was quiet, and the weird thrill was the emptiness, a four-lane road over nothing, dunes on both sides, and not another car for ten minutes at a time.

The S21, locals call it the A’wu (Altai-Urumqi) highway, is the fastest way into the Kanas country and the north. This is how to use it without wasting the desert it crosses.

The numbers that matter

The road runs roughly 360 km from the Urumqi fringe to the Altay city edge. The posted limit is 120 km/h, with section radar, so the fast cruise is real but not a place to test the needle. Toll runs about ¥0.45 to ¥0.5 per km for a car, so budget ¥170 to ¥200 each way, paid by the scan-and-go apps or cash at the booth. Fuel is the bigger planning item, because the service areas are far apart and the desert in between has none.

I treat the S21 as a fuel-hostile road: full tank in Urumqi, top up at the first service area, and never let it drop below half. The essentials list puts a jerry can in the boot for exactly this, though some rental agreements frown on it, so I ask first.

What the drive actually feels like

For the first hour it is farmland and fading suburbs, then the desert takes over and stays. The Gurbantunggut is a psammophytic desert, low dunes, grey-green scrub, and in spring a shock of yellow flowers after rain. The road is dead straight, the verges shimmer with mirage, and the wind farms on the horizon spin whether you believe the wind or not. It is boring in the best way, a moving meditation, and the light does the work. I stop once at a service area, walk the verge, and watch the dunes breathe.

The bridge sections are exposed to crosswinds that can shove a high van; I keep both hands on the wheel there and ease off in a gust. The weather read matters more on an open viaduct than in a town.

Where to get off

The S21’s job is speed, not sights, and the exits are few. The northern end drops you near Altay, the gateway to Hemu and Kanas; from there the familiar mountain roads take over. A mid-desert exit serves the small settlements and the oil-road junctions, useful if you are looping via Karamay. I would not build a day around an S21 exit for scenery; I would build the day around arriving early and fresh for the good part up north.

S21 or the old loop?

The old route, Urumqi to Karamay to Beitun, is longer but passes the Devil City and the Irtysh, and it is a better drive if the desert straight bores you. The S21 is the answer when the goal is Kanas, not the road. I use both: S21 up for speed, the Karamay loop back for the sights, a natural ring that uses each road for its strength. The train guide is the alternative if you would rather not drive the desert at all.

Pairing it with the rail

A neat trick: take the train to Urumqi, rent a car there, and run the S21 north, then fly or train back from Altay. The scenic rail guide covers the legs. It saves the long return drive and the desert twice. I have done the S21 both ways and once was enough for the straight; the mountains deserve the repeat.

Cost and comfort

Toll aside, the S21 saves a hotel night and a day, and that is the real saving. The budget guide counts days as money; shaving eight hours off the transfer is worth more than the ¥200 toll. Comfort-wise, the road is new and smooth, the rest areas clean, and the only hardship is the wind and the lack of a view change. Bring water and a playlist; the getting-around guide has the audio plan for the gaps.

Winter on the S21

The expressway stays open in winter when the mountain roads close, which makes it the reliable north-south link in the cold months. Snow squalls on the open desert can still slow it, and the crosswind bites harder, but the plows run. The snow and ice guide covers what is open when the passes shut; the S21 is often the only fast road that is. I have driven it in January and preferred it to the closed Duku every time.

A practical S21 day

Leave Urumqi at 8 a.m. with a full tank, cruise the desert by late morning, fuel at the first service area, and reach Altay for a late lunch. That leaves the afternoon for the final climb to Kanas or a rest in town. The mistake is leaving at noon, hitting the service area closed for cleaning, and sweating the fuel; the road rewards the early start like every road in Xinjiang. The Urumqi guide sets the start; the DIY planner strings the rest.

Service areas, honestly

The S21’s rest areas are new, clean and sparse, a fuel pump, a toilet, sometimes a noodle counter, and long gaps between them. I treat the first one as mandatory, not optional, because the next may be 80 km on and closed for cleaning at an awkward hour. The essentials guide lists a coolant check and a stretch; the rest area is where both happen. They are not attractions, they are insurance, and the desert teaches you to use them.

The desert flowers

People call the Gurbantunggut a dead desert and miss the point. After a spring rain it blooms, yellow and purple, for a few short weeks, and the S21 cuts right through the show. The spring-flower route is the famous one, but the northern desert has its own quiet version. I timed one April crossing to the bloom and pulled over twice just to stand in it; the straight road suddenly had a reason. Even in dry months the grey-green scrub has a texture worth a stop.

Speed cameras and the fine

Section radar means the system clocks your average, not a single point, so slowing for the camera and speeding between does not work. I set the cruise at 115 and forget it; the toll saved is less than one ticket. The essentials guide covers the gear; the discipline is free. Foreign plates are not exempt, and a fine processes through the rental or the plate, so the smooth drive is also the cheap one.

Driving it at night

The S21 at night is eerie and empty, lit only by your own beams and the occasional service-area glow. I have done it once and would not make a habit of it; the wildlife, deer and fox, crosses without looking, and the mirage of the day becomes a black void. If you must, run the limit, watch the verges, and fuel before dark. The snow and ice guide notes the winter night is worse, the plows and the whiteout both.

A fuel math example

The S21 burns about 7 L per 100 km in a car, so 360 km is roughly 25 L, call it ¥180 at ¥7 a liter, plus the ¥180 toll, about ¥360 round trip in hard costs. The budget guide puts that against a hotel night saved, and the math favors the road. I still carry the jerry can because the desert does not care about my math, and a dry tank at the 200 km mark is a walk I would rather not take.

Photography from the car

You cannot stop on the expressway except at areas, but the views through the windscreen are worth a quick frame at a pullout. The photography route guide covers the real shoots; the S21 is for the drive-by dune, the road shadow, the wind farm at dusk. I shoot through the side window at a service area, never from a moving lane, because the road demands the eyes. The desert is patient; the traffic is not.

Who the S21 suits

Time-pressed travelers, families with a Kanas deadline, and anyone who has already driven the scenic loops and wants the fast line. The first-timer FAQ often asks which road; for a first northern trip with a week, I send them the Karamay loop for sights and the S21 for the return. The road is a tool, not a trophy, and used as one it earns its place in the plan.

The back way via Karamay

If the S21 feels too straight, the old Urumqi-Karamay-Beitun route adds hours but passes the Devil City and the Irtysh bridge, a better story for the same destination. I run the S21 north and this loop south, a ring that uses each for its strength. The desert straight is a treat once; the repeat belongs to the mountains and the rock, where the driving is the point.

Charging an EV on the S21

Electric drivers ask me about the S21, and the answer is improving. The service areas have been adding charging stalls, but coverage is uneven and a dead battery in the desert is a worse problem than a dead phone, so I would not run an EV to empty between chargers. If you drive electric, charge to full in Urumqi, confirm the next stall is working before you leave the city, and keep a reserve. The EV charging guide maps the network; the S21 is on it but thin. A hybrid is the calm choice, the engine covers the gaps the plugs do not. I have watched a confident EV driver sweat the last 40 km to a stall, and the desert does not care about your range anxiety.

The mistake I made on the S21

My first S21 run I left Urumqi at noon, sure the desert was short, and hit the first service area closed for cleaning with the tank under a third. The next one was 80 km on, the wind was up, and I drove the gap watching the gauge like a hawk. I made it, fueled, and learned the rule the hard way: on a road with nothing between the areas, the early start and the full tank are not optional. The essentials guide lists the kit; the S21 is where the kit earns its keep. Now I leave by 8 a.m., fuel at the first area without exception, and treat the desert as the boss. The straight road teaches humility faster than the scenic ones.

The S21 is not the pretty road. It is the fast road, and in a short trip that is its own kind of beauty, the desert crossed before lunch, the lakes still ahead.