National significance of the motorway is reflected through its positive economic impact on the cities and towns it connects as well as its importance to tourism in Croatia.

As the route traverses rugged mountainous and coastal terrain, it has required 376 bridges, viaducts, tunnels and other similar structures in sections completed as of 2014[update], including the two longest tunnels in Croatia and two bridges comprising spans of 200 meters (660 ft) or more.

A motorway connecting Zagreb and Split was designed in the early 1970s, and a public loan was started in order to collect sufficient funds for its construction.

However, due to political upheavals in Croatia and Yugoslavia, construction of the motorway was labeled a "nationalist project" and cancelled in 1971.

[2][3] The motorway is of major importance to Croatia in terms of development of the economy; especially tourism and as a transit transport route.

[5] Once the latter motorway's connecting sections are completed, those currently spanned just by the Adriatic Highway as well as two-lane roads in Slovenia and Albania, the A1 will achieve genuine importance as a transit route.

There are numerous rest areas along the motorway, providing various types of services ranging from simple parking spaces and restrooms to petrol stations, restaurants and hotels.

[8][9][10] As of 2011[update], the motorway has 33 interchanges, providing access to numerous towns and cities and the Croatian state road network.

[12] The Bosiljevo 2 interchange distributes southbound A1 traffic flowing to Rijeka (via the A6 motorway) and to Split.

The system comprises variable traffic signs used to communicate changing driving conditions, possible restrictions and other information to motorway users.

The route also provides links to a number of UNESCO World Heritage Sites such as Plitvice Lakes, Šibenik Cathedral of St James, Palace of Diocletian in Split and the Historic City of Trogir.

Hrvatske autoceste and Autocesta Rijeka — Zagreb reported increase of the toll income compared to the same period of 2010 of 2.2% and 5% respectively.

[23][24][25] Summertime and holiday queues at Lučko mainline toll plaza can be considerable, a problem exacerbated during the usual weekend-to-weekend tourist stays at Croatia's coastal resorts.

The faster cashless system has raised the nominal capacity of the road from 2,325 to 11,150 vehicles per hour.

[29] A total of 361 structures—bridges, viaducts, flyovers, underpasses, passages, wildlife crossings, and tunnels—have been completed on the motorway between Zagreb and Vrgorac, and calculations indicate that 18.6 percent of the route between Zagreb and Split is located on those structures, which is a quite considerable percentage for a motorway of this length.

The Maslenica and Krka bridges are particularly significant as their respective main spans are 200 m (660 ft) long.

Originally the motorway was designed to follow a route from Zagreb to Bihać (Bosnia and Herzegovina) and then to Split via Knin.

The government of Bosnia and Herzegovina issued its approval for the route in Bihać region in the same year.

The funds gathered initially through the public loan were sufficient for construction of 20 kilometers (12 mi) of the motorway.

[46] The conclusion is supported by the fact the road was spontaneously nicknamed King Tomislav Motorway (Croatian: Autocesta kralja Tomislava) by citizens investing their money through the public loan after the first king of medieval Croatia, who united Croatia as a single kingdom in 925.

[47] Subsequent reorganizations of the E-road network, including the latest one in 2008, transferred the route south of Zagreb to the E71.

[45] The first attempt to revive the project in earnest occurred in the 1993, when the excavation of Sveti Rok Tunnel began.

[29] The ultimate southern terminus of the motorway was defined to be near Dubrovnik by a 2003 legislation by the Ministry of Maritime Affairs, Transport and Infrastructure.

The new interchange is only planned to be built once the A7 motorway is completed between the Rijeka bypass and Žuta Lokva.

The reported traffic volume gradually decreases as the motorway chainage increases and as it passes by various major destinations and the interchanges that serve them.

Substantial variations observed between AADT and ASDT are normally attributed to the fact that the motorway carries significant tourist traffic.

[76] Even though the rest areas found along the A1 motorway generally follow this ranking system, there are considerable variations as some of them offer extra services.

EuroTest, an international association of 18 European automobile clubs spearheaded by German automobile club ADAC, surveyed three of the A1 motorway rest areas in 2009: Krka, Lički Osik and Modruš (in case of the latter, both eastbound and westbound).

As of September 2010, there are five such rest area operators on the A1 motorway: INA, OMV, Tifon, Petrol and Crobenz.