routes.MapMvcAttributeRoutes(); //Enables Attribute Routing

routes.MapPageRoute("WebFormDefault", "", "~/Default.aspx");

routes.MapRoute(
    name: "MvcDefault",
    url: "{controller}/{action}/{id}",
    defaults: new { action = "Index", id = UrlParameter.Optional }
);

[HttpGet]
[ValidateInput(false)]
[Route("Summary/{id}", Name="GetSummary")]
public ActionResult GetSummary(int id)
{
    // blah blah blah
    return PartialView("_CardViewPartial", summaries);
}

@model Models.DoorIndexPageModel
@{
    Layout = "~/Views/Shared/_MVCPartialLayout.cshtml";
}

@Html.Action("GetSummary", new {Model.DisplayEmpId})