India: In an effort to increase the pace of construction of roads, the govt. of India is using remote sensing and radar technologies for mapping underground infrastructure like telephone lines to prevent time and cost overruns caused due to manual mapping errors.
About a third of manual groundwork studies or detailed project reports (DPRs), a prerequisite for constructing roads, are rejected for missing infrastructure details such as electricity, phone and sewage lines, leading to delays and cost overruns.
The delays led the government to adopt radars that sense utility lines beneath the ground and Light Detection and Ranging (LiDAR) technology, which uses a pulsed laser to measure distance, helping with right of way studies.
“There have been instances when utility pipelines beneath the earth were missed leading to huge cost and time overruns. Technologies such as LiDAR also takes away the discretion when deciding the alignment of a road,” said Sanjay Mitra, secretary in the ministry of road transport and highways.
“The move is also inspired by the fact that over 30% of DPRs prepared in the ministry were rejected due to human error as during surveys they missed important infrastructure,” said a senior government official requesting anonymity.
India has an ambitious highways construction goal of 41km per day. The current rate of construction is 22-23km per day.
The government had awarded 9,655km of highways construction contracts till February out of a target of 25,000km. It has also raised its construction target to 15,000km as against 6,000km constructed last year. Out of this 6,467km was constructed till February.
“With the help of LiDAR technology, we would like to minimize the human error. At present, we plan LiDAR surveys for the roads like Doimukh to Harmuti, Tura-Mankachar and Wokha-Merapani, all in the north-eastern states. The bids for these roads have already been invited,” added Mitra.
Of the total length of national highways targeted for allocation, 15,000km will come under the National Highways Authority of India (NHAI) and 10,000km under the ministry and National Highways and Infrastructure Development Corp. Ltd (NHIDCL). Similarly, NHAI’s target for construction has been fixed at 8,000km while for the ministry and NHIDCL the target is 7,000km, said Mitra.
“As the data collected by such technologies and associated photogrammetry is comprehensive, revisits to site for measurements is not needed. The system provides designers with a complete picture of the project with accurate point measurements and the ability to locate features that may be inaccessible or missed with other methods such as clearance height of high tension electricity cable,” said Bharat Lohani, professor at the Indian Institute of Technology (IIT), Kanpur.
Experts say technologies such as LiDAR save time as the survey time using mobile LiDAR is much shorter than conventional surveys. Technology allows minimum dependence on manpower, and weather and logistics factors are minimal.
“In general, the cost of LiDAR survey is found to be equal to conventional survey. On the other hand, the output from LiDAR technology is much more comprehensive, complete and reliable which are missing in the conventional technologies, especially ground-based surveying. In the long-term, LiDAR proves cheaper than conventional technologies considering the benefit the technology offers,” said Lohani.
Lohani is part of Geokno India, which introduced LiDAR technology to the Indian infrastructure industry. Geokno is promoted by the faculty members and researchers from IIT Kanpur’s geo-informatics laboratory.
The government has made several policy interventions such as increased threshold for project approval, enhanced inter-ministerial coordination, exit policy and promoting innovative project implementation models like the Hybrid Annuity Model.
“If LiDAR technology is selected worldwide, it is because it provides a much better solution in terms of cost and quality,” said Pierre de Rancourt, managing director of COWI India Pvt. Ltd, a digital mapping and GIS (geographic information system) applications firm.