[1] Completely contained in the Alajuela province, this is as of 2019 an almost straight road between San Carlos and Los Chiles, this road together with Route 4 and Route 32 allows the access between the Caribbean side of the country to the northern Alajuela districts and Nicaragua.

Since 2005 a new segment is under construction to expand the road to Route 1 towards San Jose, the project is known as the Eje Interior Norte (North Internal Axis).

[2] In Alajuela province the route covers San Carlos canton (Florencia, Cutris, Pocosol districts), Los Chiles canton (Los Chiles, El Amparo, San Jorge districts).

[6][7] Finished in September 2018, this segment connects in a more straightforward way the towns of Ciudad Quesada and Florencia.

As of 2019 there is an estimated 60% completion of this segment, however steel materials have been stolen due to the abandoned state of the project.