Between five and 10 people are caught every day trying to smuggle themselves over the UAE-Saudi Arabia border, say customs officers.
In a bid to stop them, the border patrol guards use state of the art laser technology to detect stowaways who often hide inside lorries in an attempt to cross without a passport.
"Many times the truck drivers don't even realise they have someone hiding in their truck," said one Emirati customs official.
About 50,000 lorries pass through the Al Ghuweifat border every month, an area notorious for its backlogs.
Thousands of lorries and their drivers are currently stuck at the border. They might face almost a week or more of waiting before they are granted permission to enter Saudi Arabia.
At 3pm on Wednesday, an estimated 4,000 lorries formed a queue that stretched 15 kilometres towards Abu Dhabi on the Al Ghuweifat-Sila motorway.
Another 7,000 lorries were packed into one of six lorry lots on both sides of the border, waiting for their turn to complete Saudi customs procedures.
It was taking six days for the drivers on the UAE side of the Al Ghuweifat border to snake their way across the windblown desert to reach the front of the line - a process that should only take one day.
Once through, they would have at least another day of waiting in the 5km area of "no-man's land" between the UAE and Saudi Arabia, where they would have to sit in a lot that holds 2,000 lorries .
According to customs officials, the backlog has been caused by building on the Saudi side to expand the parking area.
"When the construction stops, all these trucks will disappear."
The drivers, mainly from South Asia, were frustrated.
Many of them voiced their concerns about the lack of toilets and dwindling supplies of food and water.
The Al Ghuweifat mosque has four toilets, and a few more can be found in the handful of small eateries at the border - about eight in total for thousands of men.
An Indian driver, Iqbal Ali, who was almost at the front of the queue after waiting for six days, said it was "a big problem".
"There are not enough toilets for all of us," said Mr Ali, who was being paid Dh2,500 to transport his cargo of windows from Dubai to Riyadh.
When shouts were heard that the line had started moving, the drivers leapt into their lorries; the deafening chorus of revving engines carried down the mass of vehicles like falling dominoes.
"Six days of no washing," shouted Mr Ali as he rushed to his lorry before driving off. Only 500 metres down the road, he had to stop and turn off the engine. The waiting started all over again.
Some of the drivers were worried about their diesel tanks running dry as they again started up their massive lorries' engines to inch a little closer to the border.
Jahangi Alom, a Bangladeshi driver, arrived on Tuesday evening from Dubai with a load of lentils destined for Qatar.
He had a little gas cooker under his lorry where a pot of fish curry was slowly cooking to be ready for lunch time.
Mr Alom, who makes Dh400 per trip, said he was worried about running out of provisions.
"My water will be finished after two or three days, and the gas to cook my food is almost gone," he said. He pulled out a bag of dry crackers that he had brought with him from his home, Dhaka. It would be his only source of food before long.
The wait ahead would be gruelling, and Mr Alom knew he would be forced to ask other drivers for help when his supplies ran out. At this rate it would take him six days to reach Qatar, compared with the 10 hours it normally took.
The Punjabi driver, Manjit Singh, arrived in the queue at 6am on Wednesday with a cargo of ceramic floor tiles en route from Dubai to Damman.
"It's been like this for the past two months, so I'm very well-prepared," he said.
He owns his lorry and takes it across the border three times a month, making Dh2,200 per trip - of which Dh400 is spent on fuel and food.
He said he is used to the Saudi border being slow, but this time was "the worst" he has seen it.
The biggest problem, said Mr Singh, was when drivers jumped the queue.
"Some people are overtaking us with full loads and there is no police to stop them; we are very angry."
According to customs officials, lorries that skipped the queue were caught when they reached the border and sent all the way to the back of the line.
However, some lorries were allowed to drive straight to the front, including those carrying fresh goods like fruits and dairy products.
Empty vehicles returning to Saudi, busses with passengers and couriers, like FedEx and DHL, are also allowed to beat the queue.
Two new lorries were arriving every minute at the back of the queue, which was gradually getting shorter. At 8am on Wednesday it stretched 30km. By 1pm it was less than half that length.
According to the customs official, this backlog "is nothing". Six weeks ago there was a 70km backlog when the construction in Saudi Arabia had started, with lorries filing up two of the motorway's three lanes.
When the computer system that Saudi customs use to log the lorries crashed two weeks ago, the backlog grew even bigger.
According to lorry drivers, the Saudi border patrol officers are also notorious for disappearing from their posts for long periods of time - sometimes up to six hours - whereas the UAE side operates around the clock.
The worst backlog occurred in June 2009 when a Saudi computer system crash forced more than 6,000 lorries to wait for days in the baking summer heat.
Workers from the UAE Red Crescent Authority were dispatched at the time to distribute food and water, as well as handling diesel shortages.
The shrinking number of lorries gave the drivers hope that this would not be necessary this time around. But whether or not the queue will ever disappear completely, is another story.
