Most of what gets written about the Delhi–Mumbai Expressway focuses on speed, toll rates, and travel time. Less discussed is a genuinely unusual engineering constraint baked into its Rajasthan alignment: NE-4 was built to run through — not around — four active tiger reserves, and had to be designed accordingly.
Why This Stretch of Rajasthan Was a Problem
The most direct road corridor between Delhi and Kota happens to pass close to some of India's most ecologically significant protected forest — Ranthambore, Sariska, Mukundara Hills, and Ramgarh Vishdhari. A conventional expressway alignment through this belt would have done one of two things: forced a long, costly detour around the reserves, or cut straight through them with a solid barrier of traffic, fencing, and noise that would fragment tiger and other wildlife habitat into isolated islands — a well-documented problem on older highways elsewhere in India, where roads through forest corridors have measurably reduced genetic exchange between wildlife populations on either side.
NHAI chose neither extreme. NE-4 keeps the direct alignment through the region but incorporates dedicated crossing infrastructure specifically so animals can move between habitat patches without entering the traffic corridor.
What's Actually Built
NE-4's Rajasthan stretch includes five dedicated wildlife crossings and a tunnel through the Mukundara Hills, purpose-built for this section of the route:
- Wildlife underpasses/overpasses — structures that let animals cross beneath or above the expressway without ever reaching the carriageway, positioned at points identified as active wildlife movement corridors between forest patches
- The Mukundara Hills tunnel — rather than cutting through the hills and severing the forest canopy, the expressway tunnels underneath, leaving the surface habitat of Mukundara Hills Tiger Reserve intact above it
- Noise barrier walls — reduce the sound and light disturbance that would otherwise push wildlife away from areas near the road, even where physical crossings exist
- Fencing along sensitive stretches — channels animals toward the designated crossing points rather than allowing (or forcing) them onto the road surface directly
This is a meaningfully different approach from simply posting "wildlife crossing" warning signs, which is the extent of wildlife accommodation on most older Indian highways passing through forest areas.
The Four Reserves NE-4 Passes Near
| Reserve | State | Relevance to NE-4 | |---|---|---| | Ranthambore National Park | Rajasthan (Sawai Madhopur) | One of India's best-known tiger reserves; the expressway's Sawai Madhopur stretch runs close to its periphery | | Sariska Tiger Reserve | Rajasthan (Alwar) | Near the expressway's Haryana–Rajasthan border crossing zone | | Mukundara Hills Tiger Reserve | Rajasthan (Kota) | The expressway tunnels beneath this reserve rather than crossing its surface | | Ramgarh Vishdhari Tiger Reserve | Rajasthan (Bundi/Sawai Madhopur) | India's newest tiger reserve at the time of NE-4's planning, along the Kota-area stretch |
If you're driving through this section — roughly between Dausa and Kota — you're passing through one of the densest concentrations of tiger habitat that any Indian expressway touches.
Why This Matters Beyond Conservation
Wildlife crossings aren't purely an environmental nicety — they're also a driver safety measure. A large animal on an expressway carriageway at 120 km/h is a serious collision risk, for the animal and for vehicle occupants. Channeling wildlife toward dedicated crossing points rather than leaving them to attempt an at-grade crossing anywhere along the fence line reduces that risk on both sides. It's the same underlying logic as access-controlled design for human traffic — segregated movement is safer than mixed movement — applied to a corridor that happens to run through tiger habitat.
Driving Through the Reserve Stretch
A few practical notes if you're driving this section:
- Speed limits are reduced near wildlife crossing zones — typically around 60 km/h rather than the standard 120 km/h open-road limit, and it's worth actually observing this rather than treating it as a suggestion
- Dawn and dusk are higher-risk periods for wildlife activity near any road, expressway or not
- Don't stop on the shoulder near reserve stretches to try to spot wildlife — it defeats the purpose of the crossing infrastructure and puts you at risk from following traffic
For the full state-by-state alignment through Rajasthan and the rest of the corridor, see the Route Details page, which covers the desert, plateau, and coastal terrain NE-4 crosses on its way to Mumbai. For current speed limits in wildlife crossing zones and elsewhere on the corridor, see our NE-4 speed limit guide.
Data on reserve locations and crossing infrastructure is drawn from NHAI project documentation and public reporting on the Delhi–Mumbai Expressway's Rajasthan alignment. See our About page for full source details.