Lorry drivers are complaining of long tailbacks at the Kenyan-Ugandan border as both nations carry out mandatory coronavirus testing for them.
The East African neighbours are each other's biggest trading partners.
The border towns of Malaba and Busia, where the congestion has been centred, are crucial routes for the transport of goods.
"I haven't gone home for almost a month now, I've been stuck on this road," lorry driver Ali Muhammad told NTV.
"They keep poking my mouth every night when they do the swab test, I'm now in pain. They've even taken my blood but I don't know what the result is."
Lorry drivers delivering cargo across East Africa are among very few people allowed freedom of movement during the pandemic, the BBC's Anne Soy in Nairobi says.
Lessons from HIV
With the knowledge and experience gained from dealing with HIV and Aids, countries in the region have been quick to identify lorry drivers as a high-risk group.
At the height of the spread of HIV in the 1980s and 1990s, studies of a trucking route from the Kenya's port city of Mombasa into DR Congo's interior showed that many drivers and their crew had multiple sexual partners along the way.
Clinics and services were soon established along that route providing HIV prevention and treatment.
Eight Kenyan drivers in Uganda have recently tested positive for coronavirus, where officials have also been able to identify positive cases who were asymptomatic thanks to mandatory screening.
Tracking and swapping drivers
There have been other, more sophisticated, tracing methods in East Africa, our correspondent says.
On one occasion, a Tanzanian driver whose test returned a positive result after he had left the border was tracked down using the Uganda Revenue Authority's cargo-tracking system.
As well as mandatory testing, Kenya has also proposed relay driving, where drivers hand over vehicles to their Ugandan counterparts at the border.
This is already under way in Rwanda, where incoming transport companies are being told to swap drivers upon arrival in the country.
More regional streamlining is expected, following a virtual meeting of East Africa's health ministers over the weekend.