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eRating Levels and Criteria

eRating Levels

There are four levels of certification for a vehicle(s)* in the eRating program: e1, e2, e3, and e4.  

e1 certification represents entry-level certification and e4 certification indicates the highest level. Only the most energy efficient, lowest impacts forms of transportation are eligible for certification; a certification label on a vehicle, be it e1, e2, e3, or e4, lets consumers know that the vehicle has met a set of rigorous sustainability criteria. 


erating levels and logos

CST uses a point system, or sustainability index, to determine the certification level of a given vehicle.  Points are awarded based on a vehicle’s performance against six different criteria.  The table below shows many points are needed to attain each level of certification.

Certification Level Points Needed
250 or greater

Each criterion is weighted differently, and, as such, there are different ways that owners and operators may attain points toward certification for their vehicle(s).  


The table below shows the six criteria used to award points, as well as the range of points that can be earned in each category.

Point Ranges
Greenhouse gas emission per passenger mile
0 - 200
0 - 40
Fuel type
0 - 100
Carbon offsets
0 - 25
Training programs and policies
0 - 40
Other pro-environmental behaviors & practices
0 - 15

More specific information about the weight of each criterion, why each criterion was taken into consideration, the certification levels, and scoring system can be found in the CST program manual.

*Note: the eRating Certification is a vehicle-based certification, and does not represent the certification of a company or organization as a whole.  However, owning certified vehicles is a sign that a company is committed to sustainable transportation.  We encourage companies with certified vehicles to use our labels and marketing tools to promote their business.