Motorists travelling along the Nairobi–Nakuru highway have been warned of worsening traffic congestion as the Kenya National Highways Authority (KeNHA) flags lane indiscipline and reckless overtaking by drivers.

In a statement, the authority said the congestion is due to a significant increase in traffic volumes along various sections of the road, with lane indiscipline and overlapping vehicles being major contributors to slow movement.

“KeNHA wishes to notify motorists travelling between Nairobi and Nakuru that there has been a significant increase in traffic volumes, leading to congestion at various sections of the road. The congestion is largely due to lane indiscipline and overlapping,” the authority said.

The authority urged road users to cooperate with traffic officers and marshals and strictly follow traffic rules to prevent prolonged delays.

“Road users are urged to exercise patience, avoid overlapping, and strictly follow directions issued by traffic police officers and marshals to prevent prolonged delays,” KeNHA added.

Motorists were also reminded not to encroach onto opposing lanes of the dual carriageway, even when climbing lanes are moving slowly, as the practice poses serious safety risks.

The warning follows heavy congestion on Friday, December 19, when motorists endured long delays, with some forced to spend the night on the highway. Reports indicated gridlock stretched for several kilometres, particularly along the Mai Mahiu stretch in Naivasha and the Salgaa–Mau Summit section. Both lanes were affected, leaving public service vehicles (PSVs) and private cars stranded for over seven hours.

Ongoing roadworks contributed to slower clearance, while some drivers’ reckless overtaking further worsened the situation.

Footage shared by media outlets showed long lines of buses, trailers and private vehicles moving at a very slow pace, with some passengers and motorists spending the night in their vehicles.

KeNHA confirmed that traffic flow has since been restored along the Salgaa–Kibunja section, which had earlier experienced disruptions.

The Motorists Association of Kenya (MAK) criticised KeNHA for what it described as poor planning. MAK accused the authority of deliberately creating artificial congestion along the Salgaa–Mau Summit corridor to justify tolling public highways.

The association argued that scheduling roadworks during peak festive travel was insensitive and disrupted thousands of motorists.

“Scheduling and timing road works when thousands of Kenyans are travelling for the holidays is callous, insensitive, and directly contradicts KeNHA’s stated mandate of providing seamless connectivity,” MAK said.

The association called for accountability, transparency and planning that prioritises safety, mobility, and motorists’ dignity.

Meanwhile, the National Transport and Safety Authority (NTSA) has urged motorists to focus on safe driving, observe speed limits, maintain safe distances, use seat belts and conduct regular vehicle checks.