Google Map Route Coverage Calculation

We are into Vehcile Tracking System, and stuck into 1 development phase. Where we have created a Route for a vehcile to use throughout journey. But sometime driver use different paths instead defined one. So we need to calculate the coverage %, how much driver covered from the specified route path.

Below is FeatureCollection for Defined route:

geoJson: {type: "FeatureCollection", features: [{,…}]}
features: [{,…}]
0: {,…}
geometry: {type: "LineString",…}
properties: {Bcolor: "#FF0000", FillColor: "#FF0000", Oemid: "10", strokeColor: "#FF0000", strokeOpacity: "4.0",…}
type: "Feature"
type: "FeatureCollection"

And below is covered area coordinates:

latLong: [[77.02575, 28.44825], [77.02578166666666, 28.448081666666667],…]
[0 … 99]
0: [77.02575, 28.44825]
1: [77.02578166666666, 28.448081666666667]
2: [77.02589166666667, 28.448046666666666]
3: [77.026025, 28.448031666666665]
4: [77.026075, 28.447993333333333]
5: [77.026125, 28.447908333333334]
6: [77.02616, 28.447871666666668]

So need assistance, how to calculate covered percentage from defined route. Tried to understand Google distance api but nothing worked.