No. After 2017, an employer cannot take a business tax deduction for expenses related to the administration of a qualified transportation plan.
This is addressed in IRS Publication 15-B https://www.irs.gov/pub/irs-pdf/p15b.pdf, Employer's Tax Guide to Fringe Benefits for use in 2018. The Publication on page 20 outlines the tax treatment of qualified transportation fringe benefits to employees, including those provided through the use of salary reduction program. The Publication makes it clear that employees can continue to pay for parking and transit pass benefits on a tax free-basis through a salary reduction program after December 31, 2017. The Publication also states that the employer may not deduct any qualified transportation benefits, whether provided directly by the employer, through a bona fide reimbursement arrangement, or through a salary reduction program incurred or paid after December 31, 2017. Although the employer cannot take a business tax deduction for expenses related to the administration of a qualified transportation plan, the employer's payroll tax obligation will remain unaffected. An employer will want to consult their tax advisor for further guidance.