I think we should be able to trust our government with such data under a few conditions:
1) There should be a reasonable balance between the privacy intrusion and the benefits derived thereof
2) Data security and access restrictions to that data should be in line with the sensitivity of that data
3) The data should in principle only be used in ways for which it was collected, with a few limited and explicitly stipulated exceptions (such as law enforcement having access to subsets of the data with a court order). And always: not compelled by law to share means *forbidden* to share, no data may ever be volunteered.
4) Data retention should not be longer than needed for the purpose for which the data was collected.
5) There must be appropriate oversight to enforce these rules, with trustworthy audits and real consequences for those responsible in case of transgressions.
In many cases I do not in principle have issues with the goverment obtaining certain private data about me. However, in almost all cases, the reasonable conditions listed above are not met. In most cases, *none* of them are met.
In any case, you ought to be happy that your government at least set some limits on how and when this data can be used. When my country's government proposed a similar road pricing scheme, privacy was not addressed at all, on the contrary. No limits, any government agency would be allowed to use the data, and retention was pretty much forever. Politicians were already floating some alternative uses for the data: the police could use it to track suspicious movement, and the tax office could use it to catch fraudsters (such as catching people making private use of a company car and not declaring the milage, the way they recently did by requesting and receiving data from pay-by-smartphone parking providers). If our government sees no issue in buying data that was stolen from Swiss banks in order to catch undeclared offshore savings, they will certainly not stop short of abusing data they already own.