As an effort to counter the trend of climate change, many government organizations provide consumers with an information sheet on carbon dioxide CO2 emissions. This research is based on a set of stated preference (SP) discrete choice experiments providing respondents with emissions information and price of hypothetical vehicle alternatives. This survey include 400 respondents' socio-demographics, together with their decisions under 12 choice scenarios for each respondent (4,800 records in total). In the modeling part, WTP for CO2 emissions is the key factor that we are interested. Discrete choice models including basic conditional logit model (in preference space), structural model considering individual time preference (in WTP space), a series of mixed logit models in structural model specification with different random parameter distribution combinations, and the model considering socio-demographics are estimated. As for the estimation of mixed logit models in structural model specification, 8 combinations of distribution of random parameters are estimated, considering possible correlations. Excluding models with abnormal estimation due to WTP challenges, the uncorrelated model with both normal distributed marginal utility for price ($\alpha$) and WTP for CO2 emissions ($\omega_{E,i}$) is selected because of its lowest BIC. Its yearly subjective discount rate is 9.41%, and WTP for emissions considered time effect is $588.71. Groups of socio-demographics are included to the selected model, however, socio-demographics included are not significant in our estimation result.