The prefectural government of Oita, southwestern Japan, which maintains some 3,200 kilometers of prefectural roads, mobilizes officials for visual checks to find potholes, cracks and other road problems. With the full round of work taking four years, budgetary constraints mean that not all of the needed repairs can be carried out.

In fiscal 2016, which ended in March, the Oita government therefore introduced Fujitsu Traffic & Road Data Service Ltd.'s simple road checkup service on a trial basis. The service measures an inspection vehicle's vibrations in motion via a smartphone installed on its dashboard and indicates the degree of damage to roads in separate colors on an electronic map.

The simple checkup service proved an effective "supplement" to detailed visual inspections as data on all prefectural roads were collected quickly, said an official of the prefectural government.

The Kashiwa city office in Chiba Prefecture, east of Tokyo, recognized the effectiveness of ICT for road inspections ahead of most other local governments, introducing Fujitsu's service in June 2015.

While the Kashiwa government continues conventional checks with inspection vehicles on arterial roads out of some 1,500 kilometers of municipal roads, it cannot afford to use the costly method frequently.

As the cost of road repairs is usually lower if done quickly, "preventive" work using Fujitsu's simple checkup service can reduce the total cost of road maintenance, a Kashiwa official said.

The service has also enabled the city office to set priorities for repairs, as it quantifies the degree of deterioration not only on arterial roads but also on other roads.

While wear on roads is mostly caused by heavy-duty vehicles, the deterioration of water pipes and other objects buried under roads also causes damage in many cases. For example, mud falls into pipes through cracks created after long use, causing hollows to develop under roads.

The deterioration of sewage pipes is blamed for 3,000 to 4,000 road collapses across Japan per year. (Jiji Press)