With completion expected within days, the six-lane Guirim–Porvorim flyover promises faster journeys and long-term relief for North Goa’s congested NH-66 corridor
The countdown has begun. The contractor executing the Guirim–Porvorim flyover, RRSM Infra Private Limited, announced on July 3 that the six-lane elevated corridor is likely to be completed within the next 10–15 days, weather permitting.
For two years, Goans have read about this project only in fragments — Rs 634 crore, 5.15 kilometres, 88 piers, a collapsed segment at Sangolda, and shifting deadlines. Cost, length, spans, hurdles: that is where public knowledge of Goa’s largest road structure ends. Having studied the approved engineering drawings for the project — the plan-and-profile sheets, curve reports, and typical cross-sections issued by the PWD (NH) — I can say that the technical dimensions of this flyover make it a genuine game-changer for North Goa.
Let me elaborate. The present load on this stretch of NH-66 is an estimated 80,000 to 100,000 Passenger Car Units per day. A PCU is the traffic engineer’s honest currency — a car counts as one, a motorcycle as half, and a bus or truck as roughly three, because a truck obstructs as much road as three cars. What carries that load today is effectively a four-lane urban road interrupted by more than 20 minor junctions, bus stops, and access points over a distance of five kilometres. Standard Indian design practice rates such an interrupted arterial at barely 35,000–40,000 PCU per day.
Porvorim has thus been running at more than double its design capacity — a volume-to-capacity ratio above 2.0, which engineers call Level of Service F: forced flow, the technical name for the daily agony every commuter knows. No signal timing, and no traffic policeman can rescue a road loaded at 250 percent. Only new, physically separated capacities can. That is the flyover’s real purpose. The dimensions show how precisely the mandate has been engineered.
The corridor runs from design chainage Km 508 near Guirim to Km 513.15 at the Betim descent — about 5,150 m — executed on EPC mode by RRSM Infra of Jaipur, designed by Bridgecon Infra Consultants, Delhi. Few Goans realise that the highway performs a 70-meter climb — the height of a twenty-story building — between Guirim’s lowland, barely 4.4 meters above datum, and the Porvorim plateau at 73 meters. Eleven summit and valley curves of radii up to nearly 14,000 m tame this ascent, holding gradients within 4.7 percent, so a vehicle at speed feels neither launch nor plunge, and sightlines stay safe at night. Horizontally, the alignment is a chain of twelve curves: through Porvorim’s heart, they are 4,000 to 8,000 meters in radius — straight to the human eye — while sharper 525-, 400-, 301-, and 190-meter curves at the ends carry super elevation, a 5 percent banking of the carriageway.
The design speed is 100 km/h for almost the entire mainline, relaxing to 65 km/h only on the final bend towards Betim, which even receives 600 mm of extra pavement widening for vehicles sweeping through. The flyover’s central constraint is invisible from the road: while the right-of-way is 40 m at the approaches, it narrows to just 25 m for the central 3,890 m — Porvorim’s built-up spine. The designers fitted an expressway and a town into a 25 m space by stacking them. A single central pier in a 4.5-meter median carries a box-girder deck 24.6 meters wide: two carriageways of 10.5 meters each and three lanes of 3.5 meters each, split by an 800-mm-tall New Jersey barrier whose sloped profile redirects an errant vehicle rather than vaulting it.
Beneath, 7-meter slip roads flank the pier with a guaranteed 5.5 meters of clearance, keeping bus shelters, minor junctions, and shop front access alive at the street level. The deck sheds Goa’s three meters of monsoon rain through a 2 percent camber into 150-mm drainage pipes fitted every ten meters. The 690 m approach ramps are not earthen banks but reinforced-earth walls — soil laced with reinforcing strips behind concrete facing — chosen precisely to save width. Now, let us see the capacity arithmetic these dimensions enable. An access-controlled expressway lane passes roughly 2,000–2,200 PCU per hour; three lanes per direction yield approximately 13,000 PCU per hour for the structure, on the order of 1.2 to 1.5 lakh PCU per day at free-flow speed. The rebuilt surface system retains approximately 35,000 more local trips. Against today’s 100,000 PCU demand, the combined system will operate near a volume-to-capacity ratio of 0.6 (Level of Service B to C, stable flow) on a corridor that has lived at F. Some 60,000–70,000 PCU daily will cross Porvorim in about three minutes at height, against 30–60 minutes today.
At Goa’s 5–7 percent traffic growth, compounded by the Mopa airport, demand doubles in 11-14 years. This flyover buys us a precious decade and a half before pressure migrates to the Mandovi bridgeheads and Guirim; that window must be used to build public transport, for one bus of 40 passengers consumes three PCU, where 40 cars consume 40. When the barricades fall next month, Goans will receive not merely a flyover but a fully engineered expressway in the air, with a 10-year warranty.
(Dr Nandkumar M Kamat, who has a doctorate in microbiology, is a scientist and a science writer)
