The housing authority for the town of Trumbull applied to the defendant zoning board of appeals for a special exception to erect a fifty-unit housing complex for elderly persons and a community recreation hall pursuant to article 2, §1 (B)(6), of the Trumbull zoning regulations (1959, as amended). The selected parcel of land is 8.4 acres in area and is in a residence A zone on Machalowski Road in Trumbull. Machalowski Road is a dead-end street with about eight houses on it and would be the sole means of ingress and egress for the proposed housing complex.
The board of appeals granted the special exception, and the plaintiffs, who own property and reside near the selected site, appealed to the Court of Common Pleas. From the judgment dismissing the appeal, the plaintiffs have taken the present appeal.
The plaintiffs claim that the board of appeals acted arbitrarily and illegally in granting the special exception because one of the conditions imposed by the board was contrary to a requirement specified in the zoning regulations relating to housing projects for the elderly. We agree with this claim for reasons hereinafter stated.
As a prerequisite to granting a special exception, article 2, § 1 (B), of the Trumbull zoning regulations requires the board of appeals to find “that the existing public streets are suitable and adequate to handle any additional traffic generated by the proposed use.” In the instant case, the board of appeals found that the existing public streets had sufficient *422established right of way to be suitable and adequate to handle any additional traffic generated by the proposed use. The board noted, however, that some improvements to the right of way might be required but that they could and would be made. The board granted the special exception subject to the condition that Machalowski Road shall be widened at the direction of the town traffic commission so as to be suitable and adequate to handle the traffic generated by the housing project.
In granting the special exception, the board of appeals was acting in an administrative capacity, and its function was to determine whether the applicant’s proposal satisfied the conditions set forth in the zoning regulations relating to housing for the elderly. See RK Development Corporation v. Norwalk, 156 Conn. 369, 375, 242 A.2d 781; J & M Realty Co. v. Norwalk, 156 Conn. 185, 190, 239 A.2d 534; Jeffery v. Planning & Zoning Board of Appeals, 155 Conn. 451, 461, 232 A.2d 497; Abramson v. Zoning Board of Appeals, 143 Conn. 211, 213, 120 A.2d 827. The conditions permitting the special exception must be found in the zoning regulations themselves. Summ v. Zoning Commission, 150 Conn. 79, 87, 186 A.2d 160; Service Realty Corporation v. Planning & Zoning Board of Appeals, 141 Conn. 632, 636, 109 A.2d 256. The board of appeals could grant the special exception subject to certain conditions if the board had the authority to impose such conditions; Parish of St. Andrew’s Church v. Zoning Board of Appeals, 155 Conn. 350, 354, 232 A.2d 916; and none of the conditions imposed by the board altered any requirement prescribed in the zoning regulations. Parish of St. Andrew’s Church v. Zoning Board of Appeals, supra, 353; Huhta v. Zoning Board of Appeals, 151 Conn. 694, 697, 202 A.2d 139; *423Fox v. Zoning Board of Appeals, 146 Conn. 70, 72, 147 A.2d 472; Abramson v. Zoning Board of Appeals, supra; Mitchell Land Co. v. Planning & Zoning Board of Appeals, 140 Conn. 527, 532, 102 A.2d 316.
It is apparent that the condition imposed by the board of appeals delegated to the town traffic commission the duty of determining the extent of the traffic increase owing to the proposed housing development and what corrective measures, if any, would be required in order to accommodate this increased traffic. This condition is clearly contrary to article 2, § 1 (B), of the zoning regulations, which requires the board of appeals to determine whether the existing public streets are suitable and adequate to handle any additional traffic generated by the proposed housing development and what improvements, if any, would be necessary to provide for such increased traffic. As used in the regulations, the phrase “existing public streets” has the connotation of an area which can be used by the public for the purposes of travel by ordinary means. The phrase does not connote the total width of a public right of way regardless of its suitability for accommodating vehicular traffic. We interpret the phrase “existing public streets” to refer to the portion of a road which can be used by the public for vehicular traffic.
The board of appeals does not have the power to change one of the requirements of the zoning regulations by imposing a condition which is clearly contrary to a requirement of the regulations. The traffic commission can assist the board of appeals in its effort to determine how much additional traffic is expected to result from the housing project and what road improvements would be necessary to provide for the increased traffic. The board of appeals *424cannot, however, delegate the duty of making this determination to the town traffic commission. See Hawkes v. Town Plan & Zoning Commission, 156 Conn. 207, 212, 240 A.2d 914. In order to secure the special exception, the housing authority must show the board of appeals how much additional traffic is expected as a result of the housing project and what road improvements, if any, would be necessary to handle this increased traffic.
The condition imposed by the board of appeals is invalid. This condition is an integral part of the board’s determination, and it cannot be separated from the grant of the special exception since it indicates that the board did not make a finding that the existing public streets were suitable and adequate to handle any additional traffic generated by the proposed use. Parish of St. Andrew’s Church v. Zoning Board of Appeals, supra,, 355. The improvement of public streets involves the expenditure of public funds and the approval of municipal agencies over which the board of appeals has no control. The board should not have granted the special exception until it determined what improvements to Machalowski Road would be required and it obtained the assurance of the city that such improvements would be made. Brustein v. Zoning Commission, 151 Conn. 101, 105, 193 A.2d 523.
Since we are sustaining the plaintiffs’ appeal, we will discuss only one other claim which is likely to arise in further proceedings. As we interpret article 2, §1 (B), of the Trumbull zoning regulations, the pertinent portion of which has been set forth previously in this opinion, it is not necessary for the board of appeals to deny a special exception if it finds that the presently existing roads are not suitable and adequate to handle any increased traffic *425expected to result from the proposed use. The board may grant a special exception if it finds that road improvements can and will be made in order to handle the increased traffic.
The only sensible and reasonable meaning of this regulation is that road improvements, which the board finds are necessary, must be completed by the time that the proposed buildings are ready for use or occupancy since it is at that time that the additional traffic will commence. It is not reasonable to require the completion of road improvements before the special exception is granted because the roads would likely have to be excavated for storm sewers, water pipes, gas lines and other related matters. If road improvements were required to be completed as a condition precedent to granting the special exception, they could very well have been made needlessly since the special exception could later be denied on a variety of other grounds. For these reasons, we interpret this regulation as requiring necessary road improvements to be completed when the buildings are ready for use or occupancy and not before the board of appeals grants the special exception. See Shulman v. Zoning Board of Appeals, 154 Conn. 426, 431, 226 A.2d 380.
There is error, the judgment is set aside and the case is remanded with direction to sustain the appeal.
In this opinion King, C. J., Alcorn and Ryan, Js., concurred.