It is good to replace the halide lights, and changing the parking lot lighting into LED lighting is the trend. One of the reasons is that they can save the costs because of their high efficiency. Besides, they can last for a long time, which is suitable for outdoor lighting. You should be aware not to use LED light bulbs together with the halide fixtures. LED lights are unidirectional light sources, while halide lights are omnidirectional ones, so they cannot match with each other.
More reading: Parking Lot Lights: A Comprehensive Guide