Which is the best module to measure distance? In terms of range and reliability

Hi all,
For a project that i'm working i need to measure distance in front of a car. The purpose it to detect any obstructions in front of the car within 5-10mtr ahead. I'm planning to use multiple sr-04 ultrasound sensors. But i'm not sure about how accurate it will be. I dont need higher accurate measurement less than 50cm, but i need a sensor/radar which could detect without fail in 1-6mtr ahead.


To measure 10 meters ahead you need a narrow angle beam otherwise you will get false reflections from the road surface. Cheap ultrasonic sensors are unlikely to be suitable.
Self driving cars use a combination of LIDAR and image recognition. Neither is cheap.

LIDAR will be the best by far but as mikb55 said, it's not cheap.

Sparkfun have a LIDAR module here for ~$150 but is capable of measuring up to 40m.

A LIDAR by itself measures the position on a straight line, won't detect objects outside that line. For a broader range either multiple modules have to be used, or the beam has to move around.

I've heard of <$30 offers for LIDAR sensors, but these may be the bare sensors without optics, or production drop outs.

Since the Ultrasonic wont suite for object detection, what kind of module or radar system that i could use to sweep or scan infront of the car to detect the collision ahead?

The major car makers have been working on collision avoidance radar for decades - at about 77GHz.

It's neither easy or cheap