Estonian national road 4

National Road 4
Põhimaantee 4
Pärnu Highway
Route information
Length	192 km (119 mi)
Major junctions
From	Tallinn
Major intersections	Tallinn Järve, Tallinn Kanama Ääsmäe Märjamaa Märjamaa Pärnu Pärnu Pärnu Uulu
To	Ikla border with  Latvia
Location
Country	Estonia
Counties	Harju County  Rapla County  Pärnu County
Highway system
Transport in Estonia
← T3 → T5

Tallinn-Pärnu-Ikla maantee (Tallinn-Pärnu-Ikla highway, alternatively Põhimaantee nr 4, unofficially abbreviated T4) is a 192-kilometre-long^[1] north-south national main road in Estonia. The route follows the same path as European route E67, also known as Via Baltica. The road forms a majorly important north-south freight and travel corridor, connecting Estonia (and the rest of the Baltics) with the rest of Europe. Despite this, the only other major town serviced is Pärnu, though other main highways do branch off the T4. The highway ends on the border with Latvia in Ikla.

In 2021, the highest traffic volumes were exiting Tallinn, with AADT measured at 35,000, though this figure drops noticeably past Laagri. This is the highest recorded volume of traffic anywhere on the highway network.^[2] Being the only highway on the network that services over 1000 trucks across its entire length, congestion and dangers arising from frequent overtaking are a major issue.

The road is a dual carriageway for 13 kilometres exiting Tallinn. Isolated sections of 2+1 exist as well, however all future projects foresee a 2+2 cross-section.^[3]