Profitability is not a core principle of transportation engineering ethics because it can conflict with other important principles, such as safety and equity.

The primary responsibility of a transportation engineer is to design and build safe and efficient transportation systems that meet the needs of the public.

Accepting bribes from contractors is a clear violation of ethical principles and is illegal.

A transportation engineer should take all of the above steps to address the ethical dilemma of working on a project with potential negative environmental impacts.

Charging higher tolls for users who drive luxury vehicles is not a way to promote equity in transportation because it discriminates against certain users based on their income.

The best way to resolve ethical dilemmas in transportation engineering is to use a combination of personal judgment, consultation with colleagues and superiors, and guidance from professional ethics codes.

Promoting one's own interests above all else is not a professional responsibility of transportation engineers because it conflicts with their duty to act in a responsible and ethical manner.

All of the above factors are important to consider when making decisions about transportation projects. There is no one factor that is more important than the others.

Unethical behavior by transportation engineers can lead to loss of public trust, legal liability, and damage to the environment, but it is unlikely to lead to increased profits.

All of the above measures are important to prevent unethical behavior in transportation engineering.